Building Codes for Existing and Historic Buildings

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BUILDING CODES for Existing and Historic Buildings

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BUILDING CODES for Existing and Historic Buildings

Melvyn Green, S.E.

John Wiley & Sons, Inc.

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This book is printed on acid-free paper. Copyright © 2012 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400, fax 978-646-8600, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, 201-748-6011, fax 201-748-6008, or online at http://www.wiley.com/go/permissions. Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Portions of this publication reproduce excerpts from the 2012 International Building Code, 2012 International Existing Building Code, 2009 International Building Code, 2009 International Existing Building Code, 2006 International Building Code, 2006 International Existing Building Code, 1987 BOCA National Building Code, 1988 Standard Building Code, 1979 Uniform Building Code, and the 1976 Uniform Building Code, International Code Council, Inc., Washington, D.C. Reproduced with permission. All Rights Reserved. See the International Code Council’s website at www.iccsafe.org for downloadable products and services. For general information on our other products and services, or technical support, please contact our Customer Care Department within the United States at 800-762-2974, outside the United States at 317-572-3993 or fax 317-572-4002. Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material included with standard print versions of this book may not be included in e-books or in print-ondemand. If this book refers to media such as a CD or DVD that is not included in the version you purchased, you may download this material at http://booksupport.wiley.com. For more information about Wiley products, visit www.wiley.com. For more information about Wiley products, visit our Web site at http://www.wiley.com. Library of Congress Cataloging-in-Publication Data: Green, Melvyn. Building codes for existing and historic buildings / Melvyn Green. p. cm. Includes index. ISBN 978-0-470-19591-8 (cloth); ISBN 978-0-0470-94650-3 (ebk); ISBN 978-0-470-94652-7 (ebk); ISBN 978-0-470-94653-4 (ebk); ISBN 978-0-470-95023-4 (ebk); ISBN 978-0-470-95046-3 (ebk) 1. Historic buildings—Standards—United States. 2. Standards, Engineering—United States. 3. Building laws—United States. I. Title. TH420.G74 2011 363.6'90973—dc22 2010033337 Printed in the United States of America 10 9 8 7 6 5 4 3 2 1

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CONTENTS PREFACE xi ACKNOWLEDGMENTS xiii ABOUT MELVYN GREEN xv

PART 1

INTRODUCTION

1

CHAPTER 1 INTRODUCTION 3

How Are Building Codes Developed? 5 How Are Building Codes Applied? 5 Building Code Updates and Compliance 6 CHAPTER 2 HOW CODES REGULATE BUILDINGS 9

Understanding Code Approach

9

PART 2

DEVELOPMENT OF CODES AND STANDARDS IN THE UNITED STATES

11

CHAPTER 3 DEVELOPMENT OF BUILDING CODES IN THE UNITED STATES 13

Local Codes 15 Early Model Codes 15 Comprehensive Model Codes 16 Regional Model Codes

16

International Building Code

17

CHAPTER 4 DEVELOPMENT OF MODEL CODE PROVISIONS FOR EXISTING BUILDINGS 19

Regional Model Codes 19 International Building Code 24 Change of Occupancy Classification or Group 28 International Existing Building Code 29 v

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Contents

CHAPTER 5 DEVELOPMENT OF CODE PROVISIONS FOR HISTORIC BUILDINGS 31

Regional Model Codes 31 International Building Code Provisions for Historic Buildings 32 International Existing Building Code Provisions for Historic Buildings 33 State Building Codes for Historic Buildings 33 California 33 Massachusetts New Jersey

34

34

Federal Activities Legislation

34

34

Tax Incentives 35 Federal Agencies

35

Conclusion 37

PART 3

THE RATIONALE BEHIND CODE PROVISIONS

39

CHAPTER 6 OCCUPANCY 41

Factors Influenced or Determined by Occupancy Fire Safety Factors

41

Structural Factors

42

General Health and Safety Factors

41

42

Occupancy Classifications 42 Assembly Occupancies—Group A 43 Business Occupancies—Group B

46

Educational Occupancies—Group E

47

Factory and Industrial Occupancies—Group F High-hazard Occupancies—Group H

50

Institutional Occupancies—Group I

51

Mercantile Occupancies—Group M

55

Residential Occupancies—Group R

56

Storage Occupancies—Group S

47

58

Utility and Miscellaneous Occupancies—Group U

61

Occupancy Classifications in Previous Building Codes 61

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Contents

vii

CHAPTER 7 PLANNING AND CONSTRUCTION FACTORS 63

Siting

63

Fire Concerns

63

Health and Habitability

64

Type of Construction and Materials Type Construction Requirements Fire Concerns

64

65

69

Health and Habitability

71

Building and Component Size 71 Fire Concerns

72

Health and Habitability

72

PART 4

HOW CODES REGULATE EXISTING BUILDINGS

73

CHAPTER 8 PRINCIPLES OF REGULATING EXISTING BUILDINGS 75

What Do You Need to Know about Your Building? Building Rehabilitation and Regulation 76 Nonconforming Rights 79 Change of Occupancy 79

76

CHAPTER 9 INTERNATIONAL EXISTING BUILDING CODE COMPLIANCE METHODS 81

Why Use the International Existing Building Code? 81 How Is the IEBC Organized? 81 Alternate Materials and Methods Plan Requirements

85

85

Prescriptive Compliance Method 88 Work Area Compliance Method 89 Performance Compliance Method 89 Example Buildings 90 CHAPTER 10 INTERNATIONAL EXISTING BUILDING CODE̶PRESCRIPTIVE COMPLIANCE METHOD 97

General 97 Additions, Alterations, and Repairs 98 Structural and Seismic Requirements Nonstructural Alterations and Repairs

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99 100

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Contents

Other Requirements

100

Change of Occupancy Classification 101 Structural Requirements Conclusion

102

103

Evaluating the Prescriptive Compliance Method for a Project Prescriptive Compliance Method—Examples 105

103

CHAPTER 11 INTERNATIONAL EXISTING BUILDING CODE-WORK AREA COMPLIANCE METHOD: REPAIRS AND ALTERATIONS 111

Repairs 112 Nonstructural Repairs Structural Repairs

113

113

Alterations 115 Alteration Level 1

115

Alteration Level 2

116

Alteration Level 3

118

Work Area Compliance Method Alteration Examples 119 CHAPTER 12 INTERNATIONAL EXISTING BUILDING CODE-WORK AREA COMPLIANCE METHOD: SPECIAL CONDITIONS 125

Additions 125 Change of Occupancy 126 Change in Character of Use

131

Change to Another Occupancy Classification or Group 131 Applying the Work Area Compliance Method to Change of Occupancy Code Provisions for Change of Occupancy Classification

137

139

Historic Structures 143 Repairs to Historic Buildings

145

Alterations to Historic Buildings 145 Change of Occupancy in Historic Buildings 146 Relocated Historic Buildings 147

Work Area Compliance Method Examples 150 CHAPTER 13 INTERNATIONAL EXISTING BUILDING CODE PERFORMANCE COMPLIANCE METHOD 155

Scope 155 Additional Code Requirements 156 Performance Compliance Procedure 156 Performance Compliance Method Examples 160 Low-rise Building

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Contents

High-rise Building

ix

184

Conclusion 204 CHAPTER 14 SUMMARY OF THE COMPLIANCE METHODOLOGIES 205

Low-rise Building 205 High-rise Building 208 Summary 208

PART 5

HISTORIC PRESERVATION REGULATIONS

209

CHAPTER 15 THE LEGAL BASIS FOR HISTORIC PRESERVATION REGULATIONS 211

Federal Level 211 American Antiquities Act of 1906

211

Historic Sites Act of 1935 211 National Historic Preservation Act of 1966

212

National Environmental Policy Act of 1969

212

Executive Order 11593 of 1971

212

The Secretary of the Interior’s Standards of 1978

212

State Laws and Regulations 213 Model Code Provisions 214 Local Laws 214 CHAPTER 16 THE RATIONALE BEHIND HISTORIC PRESERVATION REGULATIONS 215

Underlying Philosophy of the Standards 215 Accuracy versus Subjectivity 215 Reproduction versus Original 217 Reversibility 217 Continuity of History 218 Examples 218 Historic Church

218

Victorian House

221

CHAPTER 17 THE IEBC AND THE SECRETARY OF THE INTERIOR S STANDARDS 223

Preservation 224 Background and Definitions Application to Specific Projects

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Preservation and Building Code Provisions

226

Rehabilitation 226 Background and Definitions Application to Specific Projects

226 227

Rehabilitation and Building Code Provisions

228

Restoration 229 Background and Definitions Application to Specific Projects

229 230

Restoration and Building Code Provisions 231

Reconstruction

232

Background and Definitions Application to Specific Projects

232 233

Reconstruction and Building Code Provisions

233

CHAPTER 18 RESOURCES 237

Historic Buildings 237 Natural Hazards Information 237 Fire Safety 238 INDEX 239

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PREFACE HOW TO USE THIS BOOK The book’s approach is cumulative, with an objective of helping the user to develop judgment about code issues and existing buildings. Rather than offer reference material that can easily be used in a piecemeal fashion, the book is intended to promote an understanding of the art of applying building regulations to the environment of existing buildings. In using this approach, a reader can learn to evaluate the reasons for code requirements and apply them in such a way as to produce an acceptable level of safety. This book can be used as a tool for practicing architects, engineers, and construction regulatory officials who deal with historic and other existing buildings. Its emphasis is on the formation of sound professional judgment concerning application of code provisions and exceptions to actual projects. The book begins with an overview of the history of building regulations in the United States, with an emphasis on events and conditions behind the development of regulations. Development of code provisions for existing and historic buildings is also detailed. Following these sections is an exploration of the rationale behind code provisions. Two kinds of factors influence this rationale: changeable and permanent. The changeable factor is occupancy, the use to which the building is put. Occupancy is important because it affects potential hazards within a building as well as the number and density of people at risk. Not every building is suitable for every occupancy. A particular occupancy may prove to be uneconomic in some buildings due to code restrictions; in the case of historic buildings, a particular occupancy choice may dictate an unacceptable level of alteration. Permanent factors include the building’s position on the property, type of construction and materials, and building and component size. They may, however, be altered in minor ways. For example, if an existing building’s windows are too close to a property line, fire sprinkler heads may be permitted to reduce the risk of transmission of fire to adjacent buildings, even though a new building would not be allowed to have windows in those locations. However, the expense of modifying permanent factors may make a project infeasible. The principles of regulating existing buildings are discussed. Basic building information, nonconforming rights, and the code’s approach to change of occupancy are included. The prescriptive, work area, and performance compliance methods of the International Existing Building Code are analyzed. Each method of compliance is described with regard to its application to particular situations, such as repairs, alterations, and change of occupancy. Examples are provided to show significant code issues. xi

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xii

Preface

Finally, there is a discussion of regulations that specifically affect the practice of historic preservation, such as the Secretary of the Interior’s Standards for Treatment of Historic Structures, model code provisions, and state and local laws. The rationale behind sometimes-mystifying historic preservation principles is discussed as well, as is the relationship between these laws and the International Existing Building Code.

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ACKNOWLEDGMENTS I would like to thank and acknowledge the many people who assisted in the development and preparation of this book. Much of the credit for preparing the text and developing the approach goes to Anne L. Watson, my associate for over twenty-five years. Loretta H. Duvall developed the case studies in the performance approach with hard work and dedication to details. Erwin R. Pascua prepared most of the graphics. On the International Code Council side, thanks to Mark Johnson for his support and Hamid Naderi for offering comments and edits. And Lis Valdemarsen and Sandra Hyde, who are on the staff of ICC and worked on this project.

xiii

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ABOUT MELVYN GREEN Melvyn Green is a structural engineer who has been in private practice for almost forty years. He specializes in historic and existing buildings. He was involved in the development of several model codes for existing buildings, including the Uniform Code for Building Conservation (UCBC), HUD’s Nationally Applicable Recommended Rehabilitation Provisions (NARRP), and the International Existing Building Code. Prior to establishing his own firm, he was Director of Building and Safety for the City of El Segundo, California. He is a past President of the Structural Engineers Association of California and a Fellow of ASCE, SEAOC, and ATPI. He is an adjunct professor at Goucher College Master’s program in historic preservation and also an adjunct professor at the University of Arizona, where he teaches design of timber and masonry buildings. He is a lecturer in the University of Southern California—Historic Preservation Certificate Program.

ABOUT THE INTERNATIONAL CODE COUNCIL The International Code Council (ICC), a membership association dedicated to building safety, fire prevention, and energy efficiency, develops the codes and standards used to construct residential and commercial buildings, including homes and schools. The mission of ICC is to provide the highest quality codes, standards, products, and services for all concerned with the safety and performance of the built environment. Most U.S. cities, counties, and states choose the International Codes, building safety codes developed by the International Code Council. The International Codes also serve as the basis for construction of federal properties around the world and as a reference for many nations outside the United States. The Code Council is also dedicated to innovation and sustainability, and Code Council subsidiary, ICC Evaluation Service, issues Evaluation Reports for innovative products and reports of Sustainable Attributes Verification and Evaluation (SAVE). Headquarters: 500 New Jersey Avenue, NW, 6th Floor, Washington, DC 20001-2070 District Offices: Birmingham, AL; Chicago. IL; Los Angeles, CA 1-888-422-7233 www.iccsafe.org

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PART

1

INTRODUCTION

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CHAPTER

1

Introduction

For many years, building codes were considered to be something of an enemy of historic preservation. And the converse was also true: the general public and some code officials regarded old buildings as hazardous. Stories of disasters in dangerous old firetraps vied with accounts of landmarks lost to overzealous code enforcement. Two worthy objectives—public safety and heritage conservation—were on a perpetual collision course. Figures 1.1 and 1.2 show two examples of historic

Figure 1.1 Mission San Gabriel, founded in 1771, illustrates the preservation issues of building codes and historic buildings. The Mission has a large number of visitors, and so requires a safe exit system, fire safety measures, and earthquake protection. © Melvyn Green

 Figure 1.2 A high-rise building, constructed in the 1920–1930 period. Similar buildings may be found in the business districts of most cities. © Melvyn Green

3

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4

Introduction

buildings, which are in current use through the effective implementation of building codes. In an effort to resolve this conflict, the National Trust for Historic Preservation sponsored a conference in 1972, inviting representatives from both sides of the issue. The idea took root, and codes began to be changed to encourage preservation of old buildings rather than demolition. Research on performance of archaic materials began, giving a background and rationale to code efforts. By the time the first International Existing Building Code (IEBC) was published in 2000, much of the conflict had been resolved. The IEBC provided technically competent methods for evaluating old buildings and rehabilitating them to meet safety requirements. This book is an aid to understanding those methods. Even as the 2006 or 2009 editions of the IEBC (seen in Figures 1.3 and 1.4) are most likely being used to varying degrees throughout the country, the 2012 IEBC is being drafted.

Figure 1.3 The 2006 International Existing Building Code (IEBC). The IEBC is a member of the International Codes family. The IEBC describes the compliance methods for work in existing buildings and how to effectively utilize them. © International Code Council

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Figure 1.4 The 2009 IEBC. Codes are always being revised based upon experience. The 2009 edition is an update to the 2006 code. It is the result of code change submittals to the International Code Council. © International Code Council

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How Are Building Codes Applied?

5

To use the IEBC effectively, it is essential to understand not only its provisions but also the intent behind those provisions. Building rehabilitation requires judgment concerning risks and hazards in buildings and the code’s role in limiting them. This, in turn, requires a comprehensive understanding of building codes, their development, and intent, and knowledge of issues of code compliance and noncompliance and the development of code alternatives.

HOW ARE BUILDING CODES DEVELOPED? Building regulations derive from different sources, and these sources must be coordinated and understood in context for regulations to be efficiently used. 

Health and safety is a basic responsibility of state government, and many states and localities have adopted building regulations to meet the specific needs and practices of their communities. This is particularly true for historic buildings.



Model codes, traditionally developed by private entities, also contain provisions for historic structures.



A recent code developed by the International Code Council (ICC) is the International Existing Building Code (IEBC). Because this code is being adopted by many states and local jurisdictions and is updated on a regular basis, it is discussed in detail in this book.



Historic preservation is also regulated at the federal level by the Secretary of the Interior’s Standards for Treatment of Historic Properties. These standards, and accompanying guidelines, have evolved to produce sophisticated guidance for good practice.

In the past few years, codes have been modified and new codes have been written to address these issues, but little has been written to help designers and code officials understand and apply these new regulations, especially as they pertain to historic preservation.

HOW ARE BUILDING CODES APPLIED? New code editions apply 

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In their entirety to new construction, including new additions to existing buildings, foundations of moved buildings, and reconstructions of historic buildings

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6

Introduction



In specified ways to rehabilitation and remodeling of existing buildings, subject to the reasoned development of alternatives that meet the intent of the code



Retroactively in rare cases when new requirements are judged to be of overriding importance to building safety

BUILDING CODE UPDATES AND COMPLIANCE Building codes are typically revised on a three-year cycle. A building may be “not in conformance with current code” by the time it is completed—even though it conforms to the code in effect at the time the permit was issued. For a 50- or 100-year-old structure, the deviation from current code is likely to be much more significant. While preservation of historic structures is generally recognized as important, the question of code compliance can be a disturbing one. What does it mean for a building to “not meet code”? Does it mean the building is unsafe? If not, why are codes updated? These questions can be puzzling to laymen, who often believe 

That a building that conforms to code requirements is “fireproof ” or “earthquake proof ”



That noncomplying buildings are suspect at best and should be made to comply as a matter of public safety



That, since compliance with current code produces a safe building, any building failure must be preventable and unreasonable

None of these popular beliefs are true, of course. Compliance with current code does not mean that a building has no vulnerabilities. Nor does noncompliance necessarily mean that significant hazards exist. Reasons for updating codes vary from including new materials to incorporating wisdom learned from recent disasters. Only rarely is new information considered to be so important that it triggers retroactive requirements. In most cases, code innovations describe construction details or techniques that are arguably an improvement over existing practice but are not essential to safety. For example, under the 1982 Uniform Building Code, the maximum stair riser height was 7½ inches; the minimum tread width was 10 inches. With the 1985 update, the maximum permitted riser was 7 inches, and the minimum tread was 11 inches. Whether the changes caused a marginal increase in stair safety is debatable. What they did do is to render most existing buildings nonconforming. To change these nonconforming stairways would require complete reconstruction of the stairwells. In a high-rise building, it would necessitate major structural work, as well as a loss of leasable space—to correct a “deficiency” that is not associated with any particular hazard or harm.

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Building Code Updates and Compliance

7

Thus, an element of judgment enters calculations about code conformance. When a code is used as an absolute standard, then a building either conforms or does not. In the case of existing buildings, that is often not the most effective or intelligent way to use the code. Instead, designers and code officials must consider means of achieving the code’s significant goals without necessarily meeting its specific details.

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CHAPTER

2

How Codes Regulate Buildings

For millennia, human beings have constructed buildings to provide safety, health, and comfort. Like many solutions, construction of shelter generates its own set of problems. Though providing protection from weather and predators, buildings may collapse, catch fire and burn, or provide an unhealthful or unsafe interior environment. Building regulations have developed in response to these problems.

UNDERSTANDING CODE APPROACH Under the U.S. Constitution, the responsibility for public safety is left up to the states. Thus, the power to regulate buildings is derived from “police power,” the right of each state to enact and enforce laws to regulate health, safety, and public welfare. Limiting hazards posed by buildings is an important part of each state’s responsibility. A key concept in building code development is that of acceptable level of risk. No activity, including that of enjoying shelter, is risk-free. Society decides what level of risk is appropriate for specific kinds of buildings and revises this decision periodically. Codes represent expert opinion, usually fairly accurate, concerning what physical characteristics are needed to achieve a level of building performance that produces acceptable risk. Historically, codes have regulated four overall risk sets: 

Life and property loss in fires. Codes originated partly to prevent fire from spreading from one building to another. In later years, provisions were tightened to attempt to prevent casualties outside the room of fire origin. Today’s codes are beginning to address preventing casualties even within the room of ignition.



Speed of exiting. A major concern in the protection of building occupants’ lives is the speed of possible exiting. Exiting can be pictured as a race between the occupants and the fire and combustion products. The outcome of the race can be improved by decreasing the fire’s head start, hastening the occupants’ escape, and reducing the fire’s speed. 9

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10

How Codes Regulate Buildings



Partial or total structural collapse under foreseeable conditions. This concern addresses natural hazards such as snow, wind, and earthquake forces, as well as normal gravity loads from construction and occupancy of the building.



General health and safety. This category includes habitability requirements such as ventilation and sanitation, accessibility, and accident prevention features, such as guardrails, steepness of stairs, and safety glazing. In recent years, energy conservation and accessibility improvements have been added to this category of regulation.

To control these risks, building codes address the following attributes of buildings and their parts: 

Occupancy—The uses permitted for a particular building or building area



Siting—Relationship of the building to the land on which it is built, to property lines, and to the streets and alleys around it



Materials of construction



Building and component size, including overall plan dimensions, height, number of stories (called “heights and areas” in building codes), size of individual compartments, ceiling heights, widths of exits, and dimensions of stair risers and treads

Each of these factors influences all the others. When a new building is designed, the occupancy and overall desired size may be the only known elements. All other characteristics emerge during the design process. In rehabilitation, however, the only completely flexible factor is occupancy. Apart from appropriate occupancy choice, rehabilitation design relies on understanding the reasons for controls on siting, materials, and sizes so that effective alternates to the letter of the code can be developed if necessary.

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PART

2

DEVELOPMENT OF CODES AND STANDARDS IN THE UNITED STATES

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CHAPTER

3

Development of Building Codes in the United States

This chapter traces the evolution of local and model building regulations and of other standards that have affected building rehabilitation in the United States. Building regulations have typically followed, and have been partly inspired by, high-profile disasters. While such events have often provided final impetus for change, other factors have also promoted reform. A single event is less likely to cause widespread change than to act as a catalyst for reforms that might have come gradually in any case.

Major City and Building Fires in the United States This list does not include fires that occurred as a result of acts of war. All listed fires caused major life and property loss. Date

Disaster

Code Action

1788 and 1794

New Orleans Conflagrations

1805

Detroit Conflagration

1811

Richmond Theater Fire

1813

Portsmouth, New Hampshire Conflagration

1820, 1854, and 1862

Troy, New York Conflagrations

1835

Great Fire of New York

Rebuilding with masonry and construction of new water system

1849

St. Louis Fire

Local requirements for masonry construction and new water system

1866

Great Fire of Portland, Maine

1871

Great Chicago Fire

The Portsmouth, New Hampshire, Brick Act of 1814

Chicago Building Code (1875) (Continued )

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14

Development of Building Codes in the United States

Date

Disaster

1871

Peshtigo, Wisconsin Fire

Code Action

1871

Great Boston Fire

1871

Port Huron Conflagration

1876

Conway’s Theater Fire, New York

1889

Great Seattle Fire

1901

Great Fire of 1901, Jacksonville, Florida

1903

Iroquois Theater Fire

1904

Great Baltimore Fire

National Building Code recommended by the National Board of Fire Underwriters (1905)

1906

San Francisco Earthquake and Fire

Codes were relaxed to permit quick reconstruction

1908

Rhodes Opera House Fire, Boyertown, Pennsylvania

1911

Triangle Shirtwaist Fire

1917

Great Atlanta Fire

1923

Berkeley, California Conflagration

1942

Coconut Grove Fire

Local zoning to create fire district

Local ordinance prohibiting wood shingles

1944

Hartford Circus Fire

Local laws banning circus tents

1946

LaSalle Hotel Fire

Local requirements for hotel safety

1958

Our Lady of Angels Fire, Chicago

Nationwide changes in school safety procedures. Local fire code changes. New amendments to Illinois state fire code.

1982

Dorothy Mae Apartments, Los Angeles

Retroactive ordinance requiring automatic sprinklers in common areas, inside entry doors into each residential unit, and fire alarm systems in buildings 3 stories and greater.

The table illustrates a number of major fires that have occurred in the United States. Many of these have resulted in building and fire code changes. Besides disasters, influences may include a series of smaller events, scientific and engineering advances that make problems more open to solution, publications by reformers, economic forces, and historical or cultural factors. Although regulation of buildings may be traced to ancient times, tension always remains between the needs of society and the rights of the property owner. This

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Early Model Codes

15

tension may result in codes evolving through clear necessity, for example, to prevent recurrence of a disaster. Simultaneously, pressure in favor of regulation may come from social reformers, civic leaders, or affected industries, such as the insurance industry.

LOCAL CODES Housing and building laws in the United States began at the level of local government and developed alongside public health regulations. The first comprehensive building law in the United States was the Tenement House Act passed by the City of New York in 1867. That may be put into context with the thennascent science of epidemiology, which is generally agreed to have begun with John Snow’s 1854 discovery that a cholera outbreak in London could be traced to a polluted well, thus establishing an indisputable scientific connection between environment and health. In the decade prior to the Tenement House Act, New York had seen wave after wave of immigration. Vast numbers of the newcomers were poor; many could not speak fluent English. Profit-minded landlords developed minimal housing in response to this demand. Health and safety conditions in these tenements were unspeakable. Spurred by both idealism and fear of contagion, the Tenement House Act addressed minimal safety and health improvements; revisions in 1879 and 1901 increased the standards to include detailed provisions for lighting, sanitation, ventilation, room size, and other characteristics. A similar alliance of reform and self-interest spurred the growth of local building regulations. Losses of life and property in several fires led to widespread support for development and enforcement of building standards. The earliest building controls were enacted at the local level, notably the Portsmouth, New Hampshire, Brick Act of 1814 and the Chicago Building Code of 1875. These reforms were urged by insurance companies as a way of controlling financial loss, and were generally supported by public outrage over the conditions that had produced the disasters.

EARLY MODEL CODES A model code is a document prepared by a group of experts who have no legislative authority. It is not written for a specific jurisdiction and is not law until it is adopted by a jurisdiction, often with modifications. Model codes make it possible for jurisdictions to benefit from professional expertise without having to maintain a staff capable of writing a code. In addition, adoption of a model code produces coordinated requirements that are more or less uniform over a wide area. This, in turn, stimulates building by removing legal complexities from the process.

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16

Development of Building Codes in the United States

Figure 3.1 The cover of the National Board of Fire Underwriters Building Code published in 1905. It was widely adopted by local jurisdictions and became the basis for many local codes. From University of California library, as scanned by Google

The earliest model code in the United States was the National Building Code recommended by the National Board of Fire Underwriters, published in 1905 in response to fire insurance losses in the Great Baltimore Fire of 1904 (Figure 3.1). The purpose of this code was to limit fire spread from the building of fire origin. Provisions included requirements for fire walls on property lines, control of roofing material, limitations on windows in fire-resistant walls, and other measures. Adopted in toto by many larger cities across the United States, the National Building Code also served as the basis for locally written codes. Because it was promulgated by an industry that was not organized for the purpose of writing codes, the document had no specified update procedure and little, if any, opportunity for public involvement in changes. In 1913, standards for fire safety in schools and factories and for building exiting were published by the National Fire Protection Association (NFPA). The standards were expanded and published in 1927 as the Building Exits Code. Intentionally limited in scope to adequate egress, this document addressed the conditions that had led to several disasters, including the Iroquois Theater Fire in 1903 and the 1911 Triangle Shirtwaist Fire. Though promulgated by a professional code-writing organization rather than by the insurance industry, the Building Exits Code did not meet the need for a professional comprehensive code because of its restricted scope. The current NFPA publication that corresponds to the Building Exits Code is the Life Safety Code, commonly called NFPA 101.

COMPREHENSIVE MODEL CODES Regional Model Codes In 1927, the Pacific Coast Building Officials promulgated the Pacific Coast Building Code, which later became the Uniform Building Code (Figure 3.2). The organization of this code differed from that of the National Building Code in that it ranked occupancies by life risk and linked fire safety criteria to specific occupancies. The code included provisions for exiting and control of material finishes. In addition, this code contained numerous structural provisions organized by building material type. The Uniform Building Code was widely used west of the Mississippi River until the adoption of the International Building Code in 2000. The National Building Code was promulgated by the insurance industry. It was the basis for most local and state codes until late in the last century.

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The Southern Building Code, later the Southern Standard Building Code (SBC), was first published by the Southern Building Code Congress in 1945. In the southern states, hurricanes were a major issue, so design for wind was an important consideration in the code. The Basic Building Code, published by the Building Officials of America (now the Building Officials and Code Administrators International) (BOCA), was first published in 1950. It served the Midwest and New England regions. BOCA later obtained the right to use the title National Building Code. Some editions of the code are called the BOCA/National Building Code. These organizations that published the three model codes were membership organizations with members from the building industry, the building regulatory community, and the public. Originally, only building officials could vote on code changes. However, the code change process was an open process involving submittals, hearings with industry and public involvement, and open advisory voting by the membership. The model building codes were updated on a three-year cycle.

International Building Code Beginning in the late 1980s, efforts were made to improve consistency and uniformity among the three model codes. By 1990, agreement was reached on consistent chapter organization in the codes, reasonably consistent occupancy definitions, and construction types. The three model codes agreed to form the International Code Council and to publish one national model code. This resulted in the publication of the 2000 edition of the International Building Code. The International Building Code is updated on a three-year cycle.

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Figure 3.2 A reprint of the cover of the first Uniform Building Code in 1927. This code is different in its organization than previous codes. It is organized by occupancy and construction requirements, structural material design, egress, and other requirements. Its organization became the basis for most later building codes. © International Code Council

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CHAPTER

4

Development of Model Code Provisions for Existing Buildings

REGIONAL MODEL CODES As soon as a building code is written or modified, a class of nonconforming buildings is created. Since adherence to code minimums produces the most inadequate building that may legally be constructed, it could be argued that nonconforming existing buildings should be raised to at least that standard. But the question of whether, how, and when existing buildings should be brought into conformance with the code is one without an easy answer. It is clearly infeasible for owners to remodel with every code change. In addition, retroactive application of laws is difficult and subject to legal challenge; the need for such action would have to be compelling. Traditionally, building codes have addressed this problem with a threefold approach. 1. The building code establishes, or refers to a code that establishes, a level of health and safety below which a building may not legally be maintained. Such codes may be called “abatement codes,” “housing codes,” “property maintenance codes,” or a similar title. Provisions of abatement codes are retroactively applied through a citation process, regardless of whether any building work had been contemplated by the owner. Failure to comply can lead to building condemnation and demolition. Abatement codes were written by each of the model code organizations and were coordinated with the building codes. 2. In cases of demonstrated need, specific code provisions may be applied retroactively to otherwise acceptable building types. An example would be the widespread retroactive requirement for smoke detectors in residences and enclosure of stairways in schools and apartment buildings. 3. Buildings that do not fall under abatement codes may be required to be upgraded as part of an approvals process for remodeling or change of use. Here the code is not being applied retroactively, because the building has previously been approved for conditions different from those proposed.

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Development of Model Code Provisions for Existing Buildings

Figure 4.1 A high-rise urban building. Such buildings often had a single stairway with a fire escape. After a series of high-rise building fires with loss of life, cities implemented retroactive stairway requirements. © Melvyn Green

Figure 4.2 The same building as in Figure 4.1 showing an exterior stairway constructed in the 1950s on the building’s exterior to resolve fire safety issues. © Melvyn Green

Efforts for safety in structures have gone on for years. Figures 4.1 and 4.2 show an added stair that was probably added in response to a retroactive provision in high-rise structures that had only a single stairway. This alteration was done in the 1950s, when there was much concern over safety in high-rise structures. An inconsistency may be noted between the minimum level of health and safety permitted in new construction and the minimum level required, under abatement codes, for a building to continue to exist. In reality, much of the work of rehabilitating buildings takes place between these two poles, in the area where a building is technically nonconforming but is not considered unsafe. As codes have developed, different methods for dealing with building rehabilitation have been tried. One attempt was the “25–50 percent rule,” under which

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Only the new work would be required to conform to the current code if the value of the rehabilitation was less than 25 percent of the assessed value of the building.



The entire building would be required to conform to the code for new construction if the value of the rehabilitation work exceeded 50 percent of the building’s assessed value.

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In cases in which the value of the rehabilitation work was between 25 and 50 percent of the building’s value, the judgment of the building official would determine the degree of compliance appropriate.

Uniform Building Code 1976 Edition SECTION 104 APPLICATION TO EXISTING BUILDINGS (a) General. Buildings or structures to which additions, alterations, or repairs are made shall comply with all the requirements for new buildings or structures except as specifically provided in this section. (b) Additions, Alterations and Repairs: More than 50 Percent. When additions, alterations, or repairs within any 12 month period exceed 50 percent of the value of an existing building or structure, such building or structure shall be made to conform to the requirements for new buildings or structures. (c) Additions, Alterations and Repairs: 25 to 50 Percent. Additions, alterations, or repairs exceeding 25 percent but not exceeding 50 percent of the value of an existing building or structure and complying with the requirements for new buildings or structures may be made to such building or structure within any 12-month period without making the entire building or structure comply. The new construction shall conform to the requirements of this Code for new building of like area, height, and occupancy. Such building or structure, including new additions, shall not exceed the areas and heights specified in this Code. (d) Additions, Alterations and Repairs: 25 Percent or Less. Structural additions, alterations, or repairs to any portion of an existing building or structure, within any 12-month period, not exceeding 25 percent of the value of the building or structure shall comply with all of the requirements for new buildings or structures, except that minor structural additions, alterations, or repairs, when approved by the Building Official, may be made with the same material of which the building or structure is constructed. Such building or structure, including new additions, shall not exceed the areas and heights specified in this Code. (e) Nonstructural, Alterations and Repairs: 25 Percent or Less. Alterations, or repairs, not exceeding 25 percent of the value of an existing building or structure, which are nonstructural and do not affect any member or part of the building or structure having required fire resistance, may be made with the same materials of which the building or structure is constructed. (g) Existing Occupancy. Buildings in existence at the time of the passage of this Code may have their existing use or occupancy continued, if such use or occupancy was legal at the time of the passage of this Code, provided such continued use is not dangerous to life. Any change in the use or occupancy of any existing building or structure shall comply with the provisions of Sections 306 and 502.

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Development of Model Code Provisions for Existing Buildings

Whether by design or accident, the 25–50 percent approach erects barriers to rehabilitation of seriously deteriorated buildings or buildings in neighborhoods where property values are low. Beyond a certain point, the rule assumes, improvements to the building are uneconomical, and, therefore, the building should be razed and replaced with a structure that conforms to the code for new construction. In practice, the 25–50 percent rule worked poorly. Property owners in economically depressed neighborhoods could not improve their buildings, because the assessed value was low compared to the cost of repairs. In addition, the necessarily slow pace of the building condemnation process left many seriously deficient structures in use. Further difficulties were caused if rehabilitation involved a change of use. Early approaches simply said that moving up in risk required compliance. For example, exterior walls of a dwelling that is 3 feet or more from a property line were not required to be fire resistant. In practice, this means that they could be constructed of wood with wood siding. Windows were not required to be rated either and most wood dwellings used simple wood sash windows. However, requirements for fire resistance of exterior walls and windows of an office are quite different, and these characteristics are quite difficult to change. As a result, conversion of a Victorian house to legal offices would have been nearly impossible. This approach resulted in the destruction of many historic buildings because literal compliance with requirements for a workable occupancy was not possible. During the mid-1970s through the mid-1980s, the model code groups made successive changes in their provisions for existing buildings. All dropped the 25–50 percent rule from the published model codes, though some local jurisdictions and states chose to retain it. Again, language and details differed, though the objective was the same. A look at the relevant provisions of the three codes during that era shows how the approach to existing buildings was changing. Overall, the direction was to avoid restrictive provisions that would prevent rehabilitation, while retaining specific safety measures for fire resistance, structural integrity, and change of occupancy. The following excerpts from codes of that era show a variety of approaches to modification of provisions for existing buildings.

Uniform Building Code 1979 Edition SECTION 104 APPLICATION TO EXISTING BUILDINGS (a) General. Buildings or structures to which additions, alterations, or repairs are made shall comply with all the requirements for new buildings or structures except as specifically provided in this section. (b) Additions, Alterations and Repairs. Additions, alterations or repairs may be made to any building or structure without requiring the existing building or structure to

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comply with all the requirements of this code provided the addition, alteration or repair conforms to that required for a new building or structure. Additions, alterations or repairs shall not cause an existing building or structure to become unsafe or overloaded. Any building so altered, which involves a change in use or occupancy, shall not exceed the height, number of stories or area permitted for new buildings. Any building plus new additions shall not exceed the height, number of stories and area specified for new buildings. Alterations or repairs to an existing building or structure which are nonstructural and do not adversely affect any structural member or any part of the building or structure having required fire resistance may be made with the same materials of which the building or structure is constructed.

BOCA National Building Code 1987 Edition SECTION 103.0 EXISTING STRUCTURES 103.1 Continuation of existing use: The legal use and occupancy of any structure existing on the date of adoption of this code, or for which it has been heretofore approved, shall be permitted to continue without change, except as specifically covered in this code, the existing structures or fire prevention codes listed in Appendix A, or as is deemed necessary by the code official for the general safety and welfare of the occupants and the public. 103.2 Change in use: It shall be unlawful to make any change in the use or occupancy of any structure or portion thereof which would subject it to any special provisions of this code with approval of the code official, and the code official’s certification that such structure meets the intent of the provisions of law governing building construction for the proposed new use and occupancy, and that such change does not result in any greater hazard to public safety or welfare. 103.3 Additions, alterations or repairs: Additions, alterations or repairs to any structure shall conform to that required of a new structure without requiring the existing structure to comply with all the requirements of this code. Additions, alterations or repairs shall not cause an existing structure to become unsafe or adversely affect the performance of the building. Any building plus new additions shall not exceed height, number of stories and area specified for new buildings. Alterations or repairs to an existing structure which are structural or adversely affect any structural member or any part of the fire resistance rating shall be made with materials required for a new structure.

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Development of Model Code Provisions for Existing Buildings

Standard Building Code 1988 Edition SECTION 101.5 EXISTING BUILDINGS 101.5.1 General. Alterations, repairs or rehabilitation work may be made to any existing building without requiring the building to comply with all the requirements of this Code provided that the alteration, repair or rehabilitation work conforms to the requirements of this Code for new construction. The Building Official shall determine the extent to which the existing system shall be made to conform to the requirements of this Code for new construction. 101.5.2 Change of Occupancy. If the occupancy classification of an existing building is changed, the building shall be made to conform to the intent of this Code as required by the Building Official.

In practice, this subjective approach to building rehabilitation worked well in sophisticated, well-staffed building departments, but was less effective in departments with fewer resources. As this limitation became apparent, all three model code groups developed separate codes and provisions for building rehabilitation. The BOCA Basic/National Existing Structures Code was published in 1984, followed by the Uniform Code for Building Conservation in 1985 and the Standard Existing Building Code in 1988. The three codes varied in scope, but all addressed the problems of existing buildings. All required that new work meet the code for new construction but relied on the judgment of the building official to determine extent of compliance required for existing building fabric. For change of occupancy, the Uniform Code for Building Conservation (UCBC) used an approach that considered the specific building features that affected life safety, spread of fire, and seismic safety. This was accomplished by the use of hazard tables that clarified the life and fire risk as well as building height and area limitations and seismic strengthening. Moving up in hazard category required code compliance, but maintaining or reducing a building’s risk level allowed acceptance of existing exits, exterior fire protection, and other systems. In the previous example of the Victorian house, an exterior wall table would have defined a business occupancy at the same risk level as a single-family dwelling. So the UCBC developed the hazard-ranking tables based on fire records and the experience of building and fire officials. For historic buildings, the impact was a major reduction in the loss of historic fabric.

INTERNATIONAL BUILDING CODE The International Building Code was first published in 2000. Regulations for existing buildings were similar to those contained in the three model codes but more extensive. The 2009 IBC uses the basic concepts of previous editions, but continues

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to evolve. The major change in both the 2009 IBC and IEBC is the division of the regulations for additions, alterations, and repairs into individual sections. Selected provisions of the 2009 IBC are shown below.

2009 International Building Code 3403.1 General. Additions to any building or structure shall comply with the requirements of this code for new construction. Alterations to the existing building or structure shall be made to ensure that the existing building or structure together with the addition are no less conforming with the provisions of this code than the existing building or structure was prior to the addition. An existing building together with its additions shall comply with the height and area provisions of Chapter 5. 3404.2 Flood hazard areas. For buildings and structures in flood hazard areas established in Section 1612.3, any alteration that constitutes substantial improvement of the existing structure, as defined in Section 1612.2, shall comply with the flood design requirements for new construction, and all aspects of the existing structure shall be brought into compliance with the requirements for new construction for flood design. For buildings and structures in flood hazard areas established in Section 1612.3, any alterations that do not constitute substantial improvement or substantial damage of the existing structure, as defined in Section 1612.2, are not required to comply with the flood design requirements for new construction. 3405.5 Flood hazard areas. For buildings and structures in flood hazard areas established in Section 1612.3, any repair that constitutes substantial improvement of the existing structure, as defined in Section 1612.2, shall comply with the flood design requirements for new construction, and all aspects of the existing structure shall be brought into compliance with the requirements for new construction for flood design. For buildings and structures in flood hazard areas established in Section 1612.3, any repairs that do not constitute substantial improvement or substantial damage of the existing structure, as defined in Section 1612.2, are not required to comply with the flood design requirements for new construction. 3403.3.1 Design live load. Where the addition does not result in increased design live load, existing gravity load-carrying structural elements shall be permitted to be evaluated and designed for live loads approved prior to the addition. If the approved live load is less than that required by Section 1607, the area designed for the nonconforming live load shall be posted with placards of approved design indicating the approved live load. Where the addition does result in increased design live load, the live load required by Section 1607 shall be used. 3404.3.1 Design live load. Where the alteration does not result in increased design live load, existing gravity load-carrying structural elements shall be permitted to be evaluated and designed for live loads approved prior to the alteration. If the (Continued)

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Development of Model Code Provisions for Existing Buildings

approved live load is less than that required by Section 1607, the area designed for the nonconforming live load shall be posted with placards of approved design indicating the approved live load. Where the alteration does result in increased design live load, the live load required by Section 1607 shall be used. 3404.4.1 Seismic. Seismic requirements for alterations shall be in accordance with this section. Where the existing seismic force-resisting system is a type that can be designated ordinary, values of R, Ω0 and Cd for the existing seismic forceresisting system shall be those specified by this code for an ordinary system unless it is demonstrated that the existing system will provide performance equivalent to that of a detailed intermediate or special system.

Chapter 34 of the IBC includes special requirements for seismic design for additions, alterations, and repairs, depending on the type of work. The provisions are not reproduced here. It regulates conditions where the addition or alteration increases the mass of the building or where additional seismic loads are increased on elements of the building’s lateral load-resisting system. However, the exception, included in the code to encourage seismic strengthening of buildings, is of importance to historic structures, as it is intended to encourage voluntary strengthening of structures.

In the 2012 International Building Code, former Section 3404.4.1 on seismic provisions for alterations is combined with provisions from the sections on additions and repairs. The combined code provision is found in the 2012 IBC Section 3401.4.3. The content of the provision is unchanged.

3404.5 Voluntary seismic improvements. Alterations to existing structural elements or additions of new structural elements that are not otherwise required by this chapter and are initiated for the purpose of improving the performance of the seismic force-resisting system of an existing structure or the performance of seismic bracing or anchorage of existing nonstructural elements shall be permitted, provided that an engineering analysis is submitted demonstrating the following: 1. The altered structure and the altered nonstructural elements are no less conforming with the provisions of this code with respect to earthquake design than they were prior to the alteration. 2. New structural elements are detailed and connected to the existing structural elements as required by Chapter 16. 3. New or relocated nonstructural elements are detailed and connected to existing or new structural elements as required by Chapter 16. 4. The alterations do not create a structural irregularity as defined in ASCE 7 or make an existing structural irregularity more severe.

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The following provisions provide guidance related to other alterations. 3401.4.2 New and replacement materials. Except as otherwise required or permitted by this code, materials permitted by the applicable code for new construction shall be used. Like materials shall be permitted for repairs and alterations, provided no hazard to life, health or property is created. Hazardous materials shall not be used where the code for new construction would not permit their use in buildings of similar occupancy, purpose and location.

Some building features, including certain plumbing and electrical materials, and nonlaminated glazing in some locations, are no longer permitted for safety reasons. The rise and run requirements for stairways changed in the 1990s. To bring a stairway up to current rise and run criteria would entail significant structural alterations as the floor opening for the stairs would probably have to be increased.

3404.6 Means of egress capacity factors. Alterations to any existing building or structure shall not be affected by the egress width factors in Section 1005.1 for new construction in determining the minimum egress widths or the minimum number of exits in an existing building or structure. The minimum egress widths for the components of the means of egress shall be based on the means of egress width factors in the building code under which the building was constructed, and shall be considered as complying means of egress for any alteration if, in the opinion of the building code official, they do not constitute a distinct hazard to life.

In the 2012 IBC, former Section 3404.6 Means of Egress Capacity Factors has been deleted. Section 3411.6 Alterations is added. An exception to this section exempts accessible means of egress requirements of Chapter 10 of the IBC from existing buildings.

2012 International Building Code 3411.6 Alterations. A facility that is altered shall comply with the applicable provisions in Chapter 11 of this code, unless technically infeasible. Where compliance with this section is technically infeasible, the alteration shall provide access to the maximum extent technically feasible. Exceptions: 1. The altered element or space is not required to be on an accessible route, unless required by Section 3411.7. (Continued)

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2. Accessible means of egress required by Chapter 10 are not required to be provided in existing facilities. 3. The alteration to Type A individually owned dwelling units within a Group R-2 occupancy shall be permitted to meet the provision for a Type B dwelling unit. 4. Type B dwelling or sleeping units required by Section 1107 of this code are not required to be provided in existing buildings and facilities undergoing a change of occupancy in conjunction with alterations where the work area is 50 percent or less of the aggregate area of the building.

CHANGE OF OCCUPANCY CLASSIFICATION OR GROUP Buildings may change use over their lifetime. Building codes have historically required meeting the current code requirements for the proposed occupancy. The code also gives the building official authority to permit a change of occupancy without full compliance, if the life and fire risk are reduced as a result of the change of occupancy. For example, one early building code classified wholesale and retail stores, office buildings, restaurants and bars of less than 100 occupants, and factories not using highly combustible materials as a single occupancy group. Changing use today could trigger the requirements for M, B, F, S, and A occupancies. There are special seismic provisions for buildings undergoing a change of occupancy. There are also several exceptions to reduce the effect on existing buildings. The provisions described earlier about seismic upgrading also apply to change of occupancy.

3408.1 Conformance. No change shall be made in the use or occupancy of any building that would place the building in a different division of the same group of occupancies or in a different group of occupancies, unless such building is made to comply with the requirements of this code for such division or group of occupancies. Subject to the approval of the building official, the use or occupancy of existing buildings shall be permitted to be changed and the building is allowed to be occupied for purposes in other groups without conforming to all the requirements of this code for those groups, provided the new or proposed use is less hazardous, based on life and fire risk, than the existing use. 3408.2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.

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3408.3 Stairways. Existing stairways in an existing structure shall not be required to comply with the requirements of a new stairway as outlined in Section 1009 where the existing space and construction will not allow a reduction in pitch or slope. 3408.4 Change of occupancy. When a change of occupancy results in a structure being reclassified to a higher occupancy category, the structure shall conform to the seismic requirements for a new structure of the higher occupancy category. Where the existing seismic force-resisting system is a type that can be designated ordinary, values of R, Ω0 and Cd for the existing seismic force-resisting system shall be those specified by this code for an ordinary system unless it is demonstrated that the existing system will provide performance equivalent to that of a detailed, intermediate or special system. Exceptions: 1. Specific seismic detailing requirements of this code or Section 1613 for a new structure shall not be required to be met where it can be shown that the level of performance and seismic safety is equivalent to that of a new structure. Such analysis shall consider the regularity, over strength, redundancy and ductility of the structure within the context of the existing and retrofit (if any) detailing provided. 2. When a change of use results in a structure being reclassified from Occupancy Category I or II to Occupancy Category III and the structure is located in a seismic map area where SDS < 0.33, compliance with the seismic requirements of this code and Section 1613 are not required.

The bottom line is that the code gives the building official latitude to allow a change of occupancy classification or group without conforming to all the requirements for that group if the new or proposed use is less hazardous than the existing use, based on life and fire risk. The provisions described earlier about seismic upgrading also apply to change of occupancy.

INTERNATIONAL EXISTING BUILDING CODE The International Existing Building Code was first published in 2003 and was republished in 2006 without major changes. The changes in the 2009 edition are beginning to reflect field experience. The IEBC approaches rehabilitation of existing buildings in a completely different way from the model codes. Three options are offered for building rehabilitation: prescriptive, work area, and performance. In the prescriptive compliance method, IEBC Chapter 3, the International Building Code is the reference document, and variations from its requirements are left to the judgment of the code official. In the work area compliance method, Chapters 4 through 12 of the 2009 IEBC, alterations and repairs are divided into four categories: repairs, Level 1, Level 2,

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Development of Model Code Provisions for Existing Buildings CHANGE OF OCCUPANCY

ALTERATION

REPAIR

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ALTERATION LEVEL 3 ALTERATION LEVEL 2 ALTERATION LEVEL 1 REPAIR

NATURE OF WORK

Figure 4.3 The graphic on the left shows the traditional approach for all existing building alterations. The graphic on the right illustrates the IEBC work area method. © Melvyn Green

LEVEL AND SCOPE OF REQUIREMENTS

LEVEL AND SCOPE OF REQUIREMENTS

CHANGE OF OCCUPANCY

CATEGORY OF WORK

and Level 3. A repair, while seemingly straightforward, does address the needs of buildings damaged by fire and natural hazards. Level 1 consists of minor alterations that do not involve structural, electrical, plumbing, or mechanical work, space configuration changes, or alteration of windows or doors. Level 2 might include any of these things, as well as projects involving reconfiguration of existing spaces. Level 3 alterations include any project where the work exceeds 50 percent of the building’s aggregate area. Requirements are cumulative; for example, Level 3 work is required to meet provisions for Levels 1 and 2 as well as special Level 3 requirements. The IEBC continues this approach of hazard tables. Tables are provided for means of egress, heights and areas, and exposure of exterior walls. (Seismic requirements are specified in a text form, described earlier in the chapter.) Figure 4.3 compares the prescriptive approach (traditional code approach), Chapter 3, and the work area method. For the performance compliance method, IEBC Chapter 13, an evaluation must be prepared, covering structural, fire safety, means of egress, and general safety. The evaluation requires numerical scoring in numerous categories, with mandatory safety scores. It offers an alternative to dependence on subjective factors.

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CHAPTER

5

Development of Code Provisions for Historic Buildings

REGIONAL MODEL CODES In 1974, the National Trust for Historic Preservation held a workshop on building codes and historic buildings. This conference brought together, for the first time, building code officials, preservationists, architects, and others concerned with the effect of building codes on the loss of historic structures. In response to this conference, proposals were made to each of the model code groups to include special provisions for historic buildings. The language in the three codes varies, though the objective—enhanced opportunities for preservation of historic structures—was the same.

Uniform Building Code 1976 Edition SECTION 104(J) HISTORIC BUILDINGS Repairs, alterations and additions necessary for the preservation, restoration, rehabilitation or continued use of a building or structure may be made without conformance to all the requirements of this Code, when authorized by the Building Official provided: 1. The building or structure has been designated by official action of the legislative body as having special historical or architectural significance. 2. Any unsafe conditions, as described in Section 203, will be corrected in accordance with approved plans. 3. Any substandard conditions will be corrected in accordance with approved plans. 4. The restored building or structure will be less hazardous, based on life and fire risk, than the existing building. (Continued)

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BOCA National Building Code 1987 Edition SECTION 513.0 SPECIAL HISTORIC BUILDINGS AND DISTRICTS 513.1 Approval. The provisions of this code relating to the construction, repair, alteration, enlargement, restoration and moving of buildings or structures shall not be mandatory for existing buildings or structures identified and classified by the state or local government authority as historic buildings, subject to the approval of the Board of Appeals, when such buildings are judged by the code official to be safe and in the interest of public health, safety and welfare regarding any proposed construction, repair, alteration, enlargement, restoration and relocation. All approvals shall be based on the applicant’s complete submission of professional architectural and engineering plans and specifications bearing the professional seal of the designer.

Standard Building Code 1988 Edition SECTION 101.6 SPECIAL HISTORIC BUILDINGS The provisions of this Code relating to the construction alteration, repairs, enlargement, restoration, relocation or moving of buildings or structures shall not be mandatory for existing buildings or structures identified and classified by the state or local jurisdiction as Historic Buildings when such buildings or structures are judged by the Building Official to be safe and in the public interest of health, safety and welfare regarding any proposed construction, alteration, repair, enlargement, restoration, relocation or moving of buildings within fire districts.

INTERNATIONAL BUILDING CODE PROVISIONS FOR HISTORIC BUILDINGS Chapter 34 of the International Building Code has provisions for historic buildings that are similar to those in the model codes.

International Building Code 2009 Edition SECTION 3409 HISTORIC BUILDINGS 3409.1 Historic buildings. The provisions of this code relating to the construction, repair, alteration, addition, restoration and movement of structures, and change of occupancy shall not be mandatory for historic buildings where such buildings are judged by the building official to not constitute a distinct life safety hazard.

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3409.2 Flood hazard areas. Within flood hazard areas established in accordance with Section 1612.3, where the work proposed constitutes substantial improvement as defined in Section 1612.2, the building shall be brought into conformance with Section 1612. Exception: Historic buildings that are: 1. Listed or preliminarily determined to be eligible for listing in the National Register of Historic Places; 2. Determined by the Secretary of the U.S. Department of Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined to qualify as an historic district; or 3. Designated as historic under a state or local historic preservation program that is approved by the Department of Interior.

INTERNATIONAL EXISTING BUILDING CODE PROVISIONS FOR HISTORIC BUILDINGS The 2003 International Existing Building Code Chapter 10, renumbered to Chapter 11 in the 2006 International Existing Building Code, offered special consideration for historic buildings. This provision has been maintained in later editions. For these provisions to be used, a report by a registered design professional might be required by the building official. Section 1101.2 calls for the report to detail: . . . each required safety feature that is in compliance with this chapter and where compliance with other chapters of these provisions would be damaging to the contributing historic features. For buildings assigned to Seismic Design Category D, E or F, a structural evaluation describing, at minimum, a complete load path and other earthquake-resistant features shall be prepared. Additionally, the report shall describe each feature that is not in compliance with these provisions and shall demonstrate how the intent of these provisions is complied with in providing an equivalent level of safety.

STATE BUILDING CODES FOR HISTORIC BUILDINGS Concurrent with the revisions to the model codes to encourage building rehabilitation, a few states developed their own approaches to building rehabilitation, particularly for work on historic buildings.

California The first of the states to address building rehabilitation was California. In 1973, the first edition of California’s State Historic Building Code was published. Now called the State Historic Building Safety Code, this code provided technical guidance

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34

Development of Code Provisions for Historic Buildings

for building officials and design professionals and established an appeals board to review disagreements between building officials and users. San Diego developed a Building Code “Cookbook” (seen in Figure 5.1) for their historic districts to help guide owners and designers through the building department process.

Massachusetts

Figure 5.1 The cover of San Diego’s Gaslamp Quarter Code “Cookbook.” The city developed this as a handbook for design professionals and owners of historic buildings to assist them in going through the regulatory process in historic districts.

Partly as a result of numerous conversions of waterfront warehouse buildings to office, housing, and retail occupancies, Massachusetts was one of the initial states to consider a new form of regulation of existing buildings. At that time, the order of occupancy groups in the building codes was arranged in order of potential for life loss, with assembly occupancies at the top of the list and others in order of decreasing hazard, down to single-family detached garages. The Massachusetts rules permitted a change of occupancy to move the building up one hazard group without complying with the requirements for the new group. These provisions were based on research at the National Bureau of Standards (NBS, now the National Institute of Standards and Technology [NIST]) to develop approaches to building rehabilitation other than those of the 25–50 percent rule.

New Jersey In the late 1990s, New Jersey enacted the New Jersey Rehabilitation Subcode. This code changed the rehabilitation code approach by considering the extent of the rehabilitation and formulating a completely new approach to change of occupancy. This code is reported to have encouraged a significant amount of revitalization in the state.

FEDERAL ACTIVITIES Legislation In 1966, the National Historic Preservation Act was passed. The legislation states that . . . although the major burdens of historic preservation have been borne and major efforts initiated by private agencies and individuals, and both should continue to play a vital role, it is nevertheless necessary and appropriate for the Federal Government to accelerate its historic preservation programs and activities, to give maximum encouragement to agencies and individuals undertaking preservation by private means, and to assist State and local governments and the National Trust for Historic Preservation in the United States to expand and accelerate their historic preservation programs and activities.

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Federal Activities

35

The act provided that historic preservation officers be designated for each state and founded the National Register of Historic Places. The National Environmental Policy Act of 1969 required federal agencies, among many other requirements to “preserve important historic, cultural, and natural aspects of our national heritage.” This law was interpreted to include not only direct federal projects, but also any project funded with federal money. For such projects, federal agencies were required to . . . include in every recommendation or report on proposals for legislation and other major Federal actions significantly affecting the quality of the human environment, a detailed statement by the responsible official on— (i) the environmental impact of the proposed action, (ii) any adverse environmental effects which cannot be avoided should the proposal be implemented, (iii) alternatives to the proposed action, (iv) the relationship between local short-term uses of man’s environment and the maintenance and enhancement of long-term productivity, and (v) any irreversible and irretrievable commitments of resources which would be involved in the proposed action should it be implemented.

Tax Incentives One of the most significant forces in the trend toward rehabilitation of older buildings has been federal rehabilitation tax credits, which were first instituted in 1976. For rehabilitation of historic income-producing property, tax credits of up to 20 percent of the cost of the rehabilitation work could be granted. This was, and remains, one of the most effective tools for preservation of historic structures ever devised. It applied to buildings eligible for the National Register of Historic Places.

Figure 5.2 The cover of a national survey of building code provisions for historic buildings. It was published in 1976 by the National Bureau of Standards (now the National Institute of Standards and Technology). Though out of date, it provides valuable information on special code provisions for historic buildings throughout the nation.

Federal Agencies Department of Commerce In 1976, the National Bureau of Standards, of the U.S. Department of Commerce, conducted a national survey of special building code provisions for historic buildings. The survey contacted the state building regulatory official in all the states and territories, the State Historical Preservation Office (SHPO) in the states and territories as well as a number of larger cities. The results of this survey were published by NBS, entitled “Survey of Building Code Provisions for Historic Structures, NBS Technical Note 918,” seen in Figure 5.2. Also in the mid-1970s, the NBS (now the NIST) initiated a project to review alternates for the 25–50 percent rule. Based on collaboration between the bureau, code

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Development of Code Provisions for Historic Buildings

officials, the three model code groups, and the National Conference of States on Building Codes and Standards (NCSBCS), the research involved reviewing how building code provisions and enforcement methods discouraged rehabilitation of buildings. This led to the concept that “any improvement” to a building should be encouraged, rather than the arbitrary traditional percentage approach. Revisions to the 25–50 percent rule in the three model codes were based in part on this project. Department of the Interior In 1977, the Secretary of the Interior’s Standards were promulgated. This document was influenced by the Venice Charter of 1964. It gave criteria for use in historic preservation design. According to the Introduction to the Standards: The intent of the Standards is to assist the long-term preservation of a property’s significance through the preservation of historic materials and features. The Standards pertain to historic buildings of all materials, construction types, sizes, and occupancy and encompass the exterior and interior of the buildings. They also encompass related landscape features and the building’s site and environment, as well as attached, adjacent, or related new construction.

The Standards are designed to retain as much as possible of a building’s historic fabric, while permitting reasonable adaptation for new uses and changing needs. Department of Housing and Urban Development and Federal Housing Administration In 1934, the Federal Housing Administration was created to stimulate the housing market and support real estate investment by instituting standards and mortgage insurance for residential buildings. Because much of the housing constructed since that time was subject to these regulations, these standards have established a minimum level for residential construction. Since building code officials needed additional support to effectively implement or encourage building rehabilitation, the Department of Housing and Urban Development (HUD), through the National Institute of Building Sciences, developed a series of Rehabilitation Guidelines. These guidelines, published in the late 1970s and early 1980s, provided information for building officials on regulatory approaches, legal aspects of rehabilitation, and a number of technical guides on exiting and fire resistance. The guidelines remain active and have been updated regularly. In 2000, HUD, using consultants and a broad review panel of users, developed the Nationally Applicable Recommended Rehabilitation Provisions (NARRP). Though the Provisions apply only to residential occupancies, they have provided background material for many state statutes. The concepts of the NARRP project became one of the major influences on the development of the International Existing Building Code.

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Conclusion

37

CONCLUSION During the latter part of the nineteenth century, and throughout the twentieth century, regulation of buildings evolved through an interplay of social forces, technical capability, individual property rights, and a growing concern for preservation of the built environment. Building codes became increasingly more uniform as local control gave way to model codes, which in turn evolved into national standards. Finally, as existing and historic buildings came to be regarded as a valuable resource rather than a hazardous liability, codes were repeatedly revised to provide more flexibility without loss of safety.

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PART

3

THE RATIONALE BEHIND CODE PROVISIONS

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CHAPTER

6

Occupancy

The earliest editions of the model codes contain requirements based on occupancy, the use to which a building is put, though the classification and grouping of occupancies has changed over time. The risk to life, particularly in fire, varies greatly with building use, and even within a single category, common variables may affect risk. Occupancy categories in earlier codes are discussed later in this chapter.

FACTORS INFLUENCED OR DETERMINED BY OCCUPANCY Fire Safety Factors 

Age of users may be occupancy related. For example, an elementary school or a rest home would be more difficult to evacuate than an occupancy mostly populated by able-bodied adults.



Condition of users is influenced by occupancy. Occupants will be asleep for part of the time they are present in any residential occupancy. Patrons of restaurants and bars may be impaired by alcohol. In hospitals and clinics, patients may be physically unable to exit without help.



Density of occupants is a special problem of some groups. Theaters, for example, have special exiting problems because the occupant density is high. In an emergency, occupants may panic if they do not see a clear and attainable exit path. The code assigns an occupant density to each occupancy, and exiting calculations must be in accordance with this density, regardless of the practical likelihood of the assigned number of occupants being in the building.



Hazardous contents are related to certain occupancies, for example, paint stores.



In some occupancies, such as offices, most users are familiar with the building and its exit paths. In others, such as hotels, most users are not. 41

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Occupancy



In occupancies where recognized authority figures are present, such as schools, exiting may be facilitated. Such occupancies may also conduct regular fire and/or emergency drills.



Some occupancies are associated with special sources of ignition. Cooking fires in restaurants would be an example.



Some occupancies, such as correctional facilities, may limit occupants’ ability to exit.



Interior finishes of walls, ceilings, and floors may promote spread of fire. In some occupancies where extension of time available for exiting is important for occupant safety, these finishes will be more tightly regulated.

Structural Factors 

Building floor loads vary by the possible occupant and contents load. The lowest floor load would be that designated for residential structures, 40 pounds per square foot (psf). Other occupancies have appropriately increased loads, with the maximum code-complying load being 250 pounds per square foot for storage structures.



Occupancy choice may imply specific minimum span. For example, a theater requires longer spans in order to provide visibility.

General Health and Safety Factors Health and hygiene and accident prevention are included in occupancy requirements. 

Stairs and railings are regulated, often by specific occupancy. In general, requirements differ from residential to nonresidential occupancies.



Requirements for water and sanitary needs are regulated by occupancy group. Differences may address number of occupants, and residential requirements are also different from nonresidential requirements.



Particularly in existing residential buildings, where children may engage in minimally supervised play, hazards from lead paint may be significant. In other occupancies, this factor may not be important.

OCCUPANCY CLASSIFICATIONS The 2009 International Building Code divides occupancies into the following categories:

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Assembly



Business



Educational



Factory and Industrial

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Occupancy Classifications



High Hazard



Institutional



Mercantile



Residential



Storage



Utility and Miscellaneous

43

The 2012 International Building Code has updated vocabulary and renumbered sections within Chapter 3 Use and Occupancy Classification. A few additional examples of occupancies have also been added to the sections; see 2012 IBC Chapter 3 for more information.

Occupancy Groups, as well as Type of Construction discussed later in this book, are noted in different ways. Occupancies are often written as A-1 (with hyphen) or A 1 (without hyphen). The type of construction may be written as V-A or V A. Regardless, it is custom and dates back to previous codes. They all mean the same thing. Even though consistency is desirable, in this book and in practice, it may be found that consistency from one code or edition to another and from one jurisdiction to another does not occur.

Assembly Occupancies̶Group A Assembly occupancies were among the first to be regulated and are still one of the most heavily regulated occupancies. Grouped as the most hazardous of the assembly occupancies are those where large audiences can be accommodated. These are the traditional large theaters that are characterized by fixed seating, including performing arts and movie theaters, as well as television and radio studios with seating for a live audience. The dramatic theater fires of the nineteenth century were one of the primary forces for development of building codes. However, assembly occupancies include various other types of use as well. Assembly uses without fixed seating include banquet halls, large restaurants and bars, and night clubs. The number of occupants in such buildings may be smaller than in a theater, but the issue of unfamiliarity with the building’s exits remains. A special problem with this type of building use in the past has been rapid flame spread enabled by decorations and other contents, resulting in multiple life loss. The possibility that occupants’ judgment may be impaired by alcohol consumption should be taken into account when considering exiting.

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Occupancy

Less hazardous assembly uses include dance halls with no food or beverage service, museums, lecture halls, indoor athletic facilities, libraries, and religious buildings. To a greater or lesser extent, assembly occupancies share a collection of risk factors. In all cases, the majority of the occupants are not familiar with the building and its exits, occupants may greatly outnumber employees, and employees are not necessarily seen as authority figures or trained for fire evacuation. A high density of occupants is an inherent part of many assembly occupancies. These factors can combine to produce panic, which may be more lethal than the emergency that required the exiting to begin with.

2009 International Building Code SECTION 303 ASSEMBLY GROUP A 303.1 Assembly Group A. Assembly Group A occupancy includes, among others, the use of a building or structure, or a portion thereof, for the gathering of persons for purposes such as civic, social or religious functions; recreation, food or drink consumption or awaiting transportation. Exceptions: 1. A building or tenant space used for assembly purposes with an occupant load of less than 50 persons shall be classified as a Group B occupancy. 2. A room or space used for assembly purposes with an occupant load of less than 50 persons and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy. 3. A room or space used for assembly purposes that is less than 750 square feet (70 m2) in area and accessory to another occupancy shall be classified as a Group B occupancy or as part of that occupancy. 4. Assembly areas that are accessory to Group E occupancies are not considered separate occupancies except when applying the assembly occupancy requirements of Chapter 11. 5. Accessory religious educational rooms and religious auditoriums with occupant loads of less than 100 are not considered separate occupancies.

Assembly occupancies shall include the following. A-1 Assembly uses, usually with fixed seating, intended for the production and viewing of the performing arts or motion pictures including, but not limited to

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Motion picture theaters



Symphony and concert halls



Television and radio studios admitting an audience



Theaters

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Occupancy Classifications

45

A-2 Assembly uses intended for food and/or drink consumption including, but not limited to 

Banquet halls



Night clubs



Restaurants



Taverns and bars

A-3 Assembly uses intended for worship, recreation, or amusement and other assembly uses not classified elsewhere in Group A including, but not limited to 

Amusement arcades



Art galleries



Bowling alleys



Community halls



Courtrooms



Dance halls (not including food or drink consumption)



Exhibition halls



Funeral parlors



Gymnasiums (without spectator seating)



Indoor swimming pools (without spectator seating)



Indoor tennis courts (without spectator seating)



Lecture halls



Libraries



Museums



Places of religious worship



Pool and billiard parlors



Waiting areas in transportation terminals

A-4 Assembly uses intended for viewing of indoor sporting events and activities with spectator seating including, but not limited to 

Arenas



Skating rinks



Swimming pools



Tennis courts

A-5 Assembly uses intended for participation in or viewing outdoor activities including, but not limited to

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Amusement park structures



Bleachers



Grandstands



Stadiums

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46

Occupancy

Business Occupancies̶Group B Typical Group B uses are stores, offices, clinics, banks, and government buildings. In addition, some training facilities would be classified as B occupancies. College buildings and any buildings for educational use beyond the twelfth grade would be classified as B occupancies. A use designated as a B occupancy would not have any special hazard, such as flammable or explosive materials, incapacitated occupants, high occupant density, or any other condition that requires special regulation. Business occupancies are generally not high risk. Though such buildings may be large in area, or, more commonly, high rise, their life risk is low. Most business buildings are occupied largely during limited hours by alert adults. In large business occupancies, an established authority structure exists, most occupants are familiar with the building, and fire drills may be conducted. In addition, business occupancies often include a higher ratio of employees to clients than is likely to be the case in assembly buildings. In an emergency, employees would be likely to help clients exit the building.

2009 International Building Code SECTION 304 BUSINESS GROUP B 304.1 Business Group B. Business Group B occupancy includes, among others, the use of a building or structure, or a portion thereof, for office, professional or service-type transactions, including storage of records and accounts. Business occupancies shall include, but not be limited to, the following: • Airport traffic control towers • Ambulatory health care facilities • Animal hospitals, kennels and pounds • Banks • Barber and beauty shops • Car wash • Civic administration • Clinic—outpatient • Dry cleaning and laundries: pick-up and delivery stations and self-service • Educational occupancies for students above the 12th grade • Electronic data processing • Laboratories: testing and research • Motor vehicle showrooms • Post offices • Print shops

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Occupancy Classifications

47

• Professional services (architects, attorneys, dentists, physicians, engineers, etc.) • Radio and television stations • Telephone exchanges • Training and skill development not within a school or academic program

Educational Occupancies̶Group E Educational occupancies include most buildings where occupants are at or below twelfth grade (an exception in the 2006 International Building Code is religious education facilities that are adjunct to a church, which would be classified as an A3 occupancy). Because the code is designed to allow for the abilities of different age groups, educational occupancies are tightly regulated, more so in buildings that are occupied by younger children than those occupied by older students. For example, unless every classroom has an exterior exit door at grade, every portion of an educational building below the level of exit discharge must be fully sprinklered. Panic hardware is required on exit doors of E occupancy rooms with greater than fifty occupants.

2009 International Building Code SECTION 305 EDUCATIONAL GROUP E 305.1 Educational Group E. Educational Group E occupancy includes, among others, the use of a building or structure, or a portion thereof, by six or more persons at any one time for educational purposes through the 12th grade. Religious educational rooms and religious auditoriums, which are accessory to places of religious worship in accordance with Section 303.1 and have occupant loads of less than 100, shall be classified as A-3 occupancies. 305.2 Day care. The use of a building or structure, or portion thereof, for educational, supervision or personal care services for more than five children older than 2½ years of age, shall be classified as a Group E occupancy.

Factory and Industrial Occupancies̶Group F Factories include buildings that house low- and moderate-hazard industrial activities, including assembly, disassembly, finishing, packaging, repair, and similar activities. Factories are characterized by comparatively low occupant density. Almost all occupants would be familiar with the building and its exit routes. Occupants would also be almost entirely limited to alert adults, who would be capable of exiting without assistance. Group F occupancies are classified according to the nature of the materials and processes involved in the work. If materials are noncombustible, an F occupancy

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48

Occupancy

would be considered low hazard; if the processes involve combustibles, it would be moderate hazard. Any industrial process that involves hazardous or explosive materials or processes would be classified not as an F, but as an H (high-hazard) occupancy.

2009 International Building Code SECTION 306 FACTORY GROUP F 306.1 Factory Industrial Group F. Factory Industrial Group F occupancy includes, among others, the use of a building or structure, or a portion thereof, for assembling, disassembling, fabricating, finishing, manufacturing, packaging, repair or processing operations that are not classified as a Group H hazardous or Group S storage occupancy. 306.2 Factory Industrial F-1 Moderate-hazard Occupancy. Factory industrial uses which are not classified as Factory Industrial F-2 Low Hazard shall be classified as F-1 Moderate Hazard and shall include, but not be limited to, the following: • Aircraft (manufacturing, not to include repair) • Appliances • Athletic equipment • Automobiles and other motor vehicles • Bakeries • Beverages; over 16-percent alcohol content • Bicycles • Boats • Brooms or brushes • Business machines • Cameras and photo equipment • Canvas or similar fabric • Carpets and rugs (includes cleaning) • Clothing • Construction and agricultural machinery • Disinfectants • Dry cleaning and dyeing • Electric generation plants • Electronics • Engines (including rebuilding) • Food processing • Furniture • Hemp products

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Occupancy Classifications

49

• Jute products • Laundries • Leather products • Machinery • Metals • Millwork (sash & door) • Motion pictures and television filming (without spectators) • Musical instruments • Optical goods • Paper mills or products • Photographic film • Plastic products • Printing or publishing • Recreational vehicles • Refuse incineration • Shoes • Soaps and detergents • Textiles • Tobacco • Trailers • Upholstering • Wood; distillation • Woodworking (cabinet) 306.3 Factory Industrial F-2 Low-hazard Occupancy. Factory industrial uses that involve the fabrication or manufacturing of noncombustible materials which during finishing, packing or processing do not involve a significant fire hazard shall be classified as F-2 occupancies and shall include, but not be limited to, the following: • Beverages; up to and including 16-percent alcohol content • Brick and masonry • Ceramic products • Foundries • Glass products • Gypsum • Ice • Metal products (fabrication and assembly)

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50

Occupancy

High-hazard Occupancies̶Group H High-hazard occupancies are clearly specified. They include buildings in which highly flammable, explosive, or other hazardous substances or processes are housed. These occupancies have detailed, specific regulations to contain and minimize the identified hazards. This occupancy has been expanded in recent decades to incorporate numerous new materials and processes that are deemed to be hazardous. H occupancies are divided into Groups H-1 through H-5, depending on the type of hazard involved. Buildings containing processes that would be covered by more than one group must meet the requirements for all groups that apply. Special requirements occur throughout the code for high-hazard occupancies. They include requirements for fire extinguishing equipment, exclusion from exceptions, and compartmentation and venting requirements, to name a few.

High-hazard, Group H, occupancies have increased and have been revised over the years as a function of manufacturing and technology. Always review earlier codes when working with H occupancies to determine how the changes may affect a specific building project.

2009 International Building Code SECTION 307 HIGH-HAZARD GROUP H 307.1 High-hazard Group H. High-hazard Group H occupancy includes, among others, the use of a building or structure, or a portion thereof, that involves the manufacturing, processing, generation or storage of materials that constitute a physical or health hazard in quantities in excess of those allowed in control areas complying with Section 414, based on the maximum allowable quantity limits for control areas set forth in Tables 307.1(1) and 307.1(2). Hazardous occupancies are classified in Groups H-1, H-2, H-3, H-4 and H-5 and shall be in accordance with this section, the requirements of Section 415 and the International Fire Code. Hazardous materials stored, or used on top of roofs or canopies shall be classified as outdoor storage or use and shall comply with the International Fire Code. Exceptions: The following shall not be classified as Group H, but shall be classified as the occupancy that they most nearly resemble. 1. Buildings and structures occupied for the application of flammable finishes, provided that such buildings or areas conform to the requirements of Section 416 and the International Fire Code. 2. Wholesale and retail sales and storage of flammable and combustible liquids in mercantile occupancies conforming to the International Fire Code. 3. Closed piping system containing flammable or combustible liquids or gases utilized for the operation of machinery or equipment.

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Occupancy Classifications

51

4. Cleaning establishments that utilize combustible liquid solvents having a flash point of 140°F (60°C) or higher in closed systems employing equipment listed by an approved testing agency, provided that this occupancy is separated from all other areas of the building by 1-hour fire barriers constructed in accordance with Section 707 or 1-hour horizontal assemblies constructed in accordance with Section 712, or both. 5. Cleaning establishments that utilize a liquid solvent having a flash point at or above 200°F (93°C). 6. Liquor stores and distributors without bulk storage. 7. Refrigeration systems. 8. The storage or utilization of materials for agricultural purposes on the premises. 9. Stationary batteries utilized for facility emergency power, uninterrupted power supply or telecommunication facilities, provided that the batteries are provided with safety venting caps and ventilation is provided in accordance with the International Mechanical Code. 10. Corrosives shall not include personal or household products in their original packaging used in retail display or commonly used building materials. 11. Buildings and structures occupied for aerosol storage shall be classified as Group S-1, provided that such buildings conform to the requirements of the International Fire Code. 12. Display and storage of nonflammable solid and nonflammable or noncombustible liquid hazardous materials in quantities not exceeding the maximum allowable quantity per control area in Group M or S occupancies complying with Section 414.2.5. 13. The storage of black powder, smokeless propellant and small arms primers in Groups M and R-3 and special industrial explosive devices in Groups B, F, M and S, provided such storage conforms to the quantity limits and requirements prescribed in the International Fire Code.

Institutional Occupancies̶Group I Institutional occupancies include hospitals, prisons, convalescent facilities, and similar uses where either the liberty of occupants is restrained or where their physical condition would be likely to render many occupants unable to fend for themselves in an emergency.

Institutional occupancies have also changed and have been revised through the years. Some of this may reflect changes in medical care and the fact that patients in hospitals are much sicker now than years ago. The growth of specialized facilities for dementia patients is another example of changes of use.

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52

Occupancy

Institutional occupancies are grouped depending on the occupants’ ability to respond to an emergency situation. I-1 occupancies include board and care facilities, assisted living facilities, various kinds of group homes and rehab centers, and convalescent facilities with more than 16 occupants. In this group, occupants are considered to be capable of selfpreservation, both mentally and physically. An occupancy of this kind that has five or fewer occupants would be classified as an R-3 residential occupancy. Where the number of occupants are between 6 and 16, the occupancy would be R-4. I-2 occupancies would be those used for medical, surgical, nursing, or psychiatric care for patients who are not capable of self-preservation. In an I-2 occupancy, users would be present on a 24-hour basis. (An outpatient center, with users who do not stay overnight in the facility, would be classified as a B, not an I, occupancy.) A hospital or similar use would be an I-2 occupancy. I-3 occupancies include a number of uses where the occupants are physically capable of self-preservation, but their liberties are restrained. The category is further subdivided depending on the specifics of occupant restraint. I-4 occupancies include custodial day care facilities for more than five occupants by professional caregivers. The definition of this occupancy is precise and detailed, and several exceptions are provided.

2009 International Building Code SECTION 308 INSTITUTIONAL GROUP I 308.1 Institutional Group I. Institutional Group I occupancy includes, among others, the use of a building or structure, or a portion thereof, in which people are cared for or live in a supervised environment, having physical limitations because of health or age are harbored for medical treatment or other care or treatment, or in which people are detained for penal or correctional purposes or in which the liberty of the occupants is restricted. Institutional occupancies shall be classified as Group I-1, I-2, I-3 or I-4. 308.2 Group I-1. This occupancy shall include buildings, structures or parts thereof housing more than 16 persons, on a 24-hour basis, who because of age, mental disability or other reasons, live in a supervised residential environment that provides personal care services. The occupants are capable of responding to an emergency situation without physical assistance from staff. This group shall include, but not be limited to, the following: • Alcohol and drug centers • Assisted living facilities • Congregate care facilities • Convalescent facilities

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Occupancy Classifications

53

• Group homes • Halfway houses • Residential board and care facilities • Social rehabilitation facilities A facility such as the above with five or fewer persons shall be classified as a Group R-3 or shall comply with the International Residential Code in accordance with Section 101.2. A facility such as above, housing at least six and not more than 16 persons, shall be classified as Group R-4. 308.3 Group I-2. This occupancy shall include buildings and structures used for medical, surgical, psychiatric, nursing or custodial care for persons who are not capable of self-preservation. This group shall include, but not be limited to, the following: • Child care facilities • Detoxification facilities • Hospitals • Mental hospitals • Nursing homes 308.4 Group I-3. This occupancy shall include buildings and structures that are inhabited by more than five persons who are under restraint or security. An I-3 facility is occupied by persons who are generally incapable of self-preservation due to security measures not under the occupants’ control. This group shall include, but not be limited to, the following: • Correctional centers • Detention centers • Jails • Prerelease centers • Prisons • Reformatories Buildings of Group I-3 shall be classified as one of the occupancy conditions indicated in Sections 308.4.1 through 308.4.5 (see Section 408.1). 308.4.1 Condition 1. This occupancy condition shall include buildings in which free movement is allowed from sleeping areas, and other spaces where access or occupancy is permitted, to the exterior via means of egress without restraint. A Condition 1 facility is permitted to be constructed as Group R. 308.4.2 Condition 2. This occupancy condition shall include buildings in which free movement is allowed from sleeping areas and any other occupied smoke compartment to one or more other smoke compartments. Egress to the exterior is impeded by locked exits. (Continued)

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Occupancy

308.4.3 Condition 3. This occupancy condition shall include buildings in which free movement is allowed within individual smoke compartments, such as within a residential unit comprised of individual sleeping units and group activity spaces, where egress is impeded by remote-controlled release of means of egress from such a smoke compartment to another smoke compartment. 308.4.4 Condition 4. This occupancy condition shall include buildings in which free movement is restricted from an occupied space. Remote-controlled release is provided to permit movement from sleeping units, activity spaces and other occupied areas within the smoke compartment to other smoke compartments. 308.4.5 Condition 5. This occupancy condition shall include buildings in which free movement is restricted from an occupied space. Staff-controlled manual release is provided to permit movement from sleeping units, activity spaces and other occupied areas within the smoke compartment to other smoke compartments. 308.5 Group I-4, day care facilities. This group shall include buildings and structures occupied by persons of any age who receive custodial care for less than 24 hours by individuals other than parents or guardians, relatives by blood, marriage or adoption, and in a place other than the home of the person cared for. A facility such as the above with five or fewer persons shall be classified as a Group R-3 or shall comply with the International Residential Code in accordance with Section 101.2. Places of worship during religious functions are not included. 308.5.1 Adult care facility. A facility that provides accommodations for less than 24 hours for more than five unrelated adults and provides supervision and personal care services shall be classified as Group I-4. Exception: A facility where occupants are capable of responding to an emergency situation without physical assistance from the staff shall be classified as Group R-3. 308.5.2 Child care facility. A facility that provides supervision and personal care on less than a 24-hour basis for more than five children 2½ years of age or less shall be classified as Group I-4. Exception: A child day care facility that provides care for more than five but no more than 100 children 2½ years or less of age, when the rooms where such children are cared for are located on the level of exit discharge serving such rooms and each of these child care rooms has an exit door directly to the exterior, shall be classified as Group E.

The 2012 IBC Section 308.6 Institutional Group I-4, day care facilities, contains the most changes within this chapter and has been included below. Note adult and child day care facilities have been placed together. Requirements are now based on the number of people within the care facility and the facility type.

2012 International Building Code 308.6 Institutional Group I-4, day care facilities. This group shall include buildings and structures occupied by more than 5 persons of any age who

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Occupancy Classifications

55

receive custodial care for fewer than 24 hours per day by persons other than parents or guardians, relatives by blood, marriage or adoption, and in a place other than the home of the person cared for. This group shall include, but not be limited to, the following: Adult day care Child day care 308.6.1 Classification as Group E. A child day care facility that provides custodial care for more than five but no more than 100 children 2½ years or less of age, when the rooms where such children are cared for are located on the level of exit discharge serving such rooms and each of these child care rooms has an exit door directly to the exterior, shall be classified as Group E. 308.6.2 Within a place of worship. Rooms and spaces within places of religious worship providing such care during religious functions shall be classified as part of the primary occupancy. 308.6.3 Five or fewer occupants receiving care. A facility having five or fewer persons receiving custodial care shall be classified as part of the primary occupancy. 308.6.4 Five or fewer occupants receiving care in a dwelling unit. A facility such as the above within a dwelling unit and having five or fewer persons receiving custodial care shall be classified as a Group R-3 occupancy or shall comply with the International Residential Code.

Mercantile Occupancies̶Group M Mercantile occupancies, particularly large department stores, may have a combination of hazards. Such buildings may have high-piled stock, much of which may be combustible, some even hazardous. The number of customers is likely to far exceed the number of employees, especially during holiday shopping seasons and sales. Most of the occupants would not be familiar with the building’s exits, particularly in multilevel stores where few customers would know the locations of stairs. In these conditions, quick spread of fire is not unlikely, and panic is a real possibility. Though the United States experience with fires in mercantile occupancies has not been severe, other countries, including France, Belgium, Paraguay, the Philippines, Japan, and South Korea, have had notable disasters in department stores and similar buildings. Quantities of aerosols and flammable liquids are limited in Group M occupancies, and sprinklers are required if the Group M area in a building exceeds 12,000 square feet, where the occupancy is more than three stories above grade, or where all combined Group M areas in the building exceed 24,000 square feet. Sprinklers are also required where storage of merchandise is in high-piled or rack facilities.

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Occupancy

2009 International Building Code SECTION 309 MERCANTILE GROUP M 309.1 Mercantile Group M. Mercantile Group M occupancy includes, among others, the use of a building or structure or a portion thereof, for the display and sale of merchandise and involves stocks of goods, wares or merchandise incidental to such purposes and accessible to the public. Mercantile occupancies shall include, but not be limited to, the following: • Department stores • Drug stores • Markets • Motor fuel-dispensing facilities • Retail or wholesale stores • Sales rooms 309.2 Quantity of hazardous materials. The aggregate quantity of nonflammable solid and nonflammable or noncombustible liquid hazardous materials stored or displayed in a single control area of a Group M occupancy shall not exceed the quantities in Table 414.2.5(1).

Residential Occupancies̶Group R Residential occupancies consist of one- and two-family dwellings, apartments, hotels, dormitories, and residential care facilities. In residential occupancies more than any other, the question of individual versus community rights arises, particularly for privately owned single-family dwellings. This is probably why these structures have the worst fire record of all the occupancies. One of the ironies of the fire record is that more lives are lost each year, one by one, in home fires than in dramatic fires in crowded public buildings, but it remains harder to regulate residences. Residential occupancies are divided into categories based on number of occupants and type of use, but they share some common hazards. By definition, occupants are asleep for part of the time they occupy a residential building. Cooking and smoking ignition sources are likely to exist. Alcohol, drugs, or medications may play a part in casualties in this occupancy to a larger extent than in most others. In some residential occupancies, users are likely to be familiar with the space; in others, such as hotels, they are not likely to have used or noticed fire exits as they entered the building. In residential care facilities, residents may be more or less disabled or disoriented and may not be capable of effective efforts at self-preservation. In addition, residents of such facilities are likely to greatly outnumber staff, particularly at night.

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57

Fatal residential fires often begin with a cigarette smoldering—lost between cushions in upholstered furniture or otherwise concealed for several hours. Smoke detectors, if installed and functioning, should prevent fatalities from such fires. Unfortunately, functioning smoke detectors are far from universal, even after several decades of their promotion.

2009 International Building Code SECTION 310 RESIDENTIAL GROUP R 310.1 Residential Group R. Residential Group R includes, among others, the use of a building or structure, or a portion thereof, for sleeping purposes when not classified as an Institutional Group I or when not regulated by the International Residential Code in accordance with Section 101.2. Residential occupancies shall include the following: R-1 Residential occupancies containing sleeping units where the occupants are primarily transient in nature, including: • Boarding houses (transient) • Hotels (transient) • Motels (transient) Congregate living facilities (transient) with 10 or fewer occupants are permitted to comply with the construction requirements for Group R-3. R-2 Residential occupancies containing sleeping units or more than two dwelling units where the occupants are primarily permanent in nature, including: • Apartment houses • Boarding houses (not transient) • Convents • Dormitories • Fraternities and sororities • Hotels (nontransient) • Live/work units • Monasteries • Motels (nontransient) • Vacation timeshare properties Congregate living facilities with 16 or fewer occupants are permitted to comply with the construction requirements for Group R-3. (Continued)

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Occupancy

R-3 Residential occupancies where the occupants are primarily permanent in nature and not classified as Group R-1, R-2, R-4 or I, including: • Buildings that do not contain more than two dwelling units. • Adult care facilities that provide accommodations for five or fewer persons of any age for less than 24 hours. • Child care facilities that provide accommodations for five or fewer persons of any age for less than 24 hours. • Congregate living facilities with 16 or fewer persons. Adult and child care facilities that are within a single-family home are permitted to comply with the International Residential Code. R-4 Residential occupancies shall include buildings arranged for occupancy as residential care/assisted living facilities including more than five but not more than 16 occupants, excluding staff. Group R-4 occupancies shall meet the requirements for construction as defined for Group R-3, except as otherwise provided for in this code, or shall comply with the International Residential Code provided the building is protected by an automatic sprinkler system installed in accordance with Section 903.2.7.

Storage Occupancies̶Group S Storage occupancies are classified as moderate- or low-hazard use, depending on the materials stored. Life risk is small, because the buildings have few occupants. Group S is divided into moderate-hazard, S-1, and low-hazard, S-2. The division is based on combustibility of the materials stored.

2009 International Building Code SECTION 311 STORAGE GROUP S 311.1 Storage Group S. Storage Group S occupancy includes, among others, the use of a building or structure, or a portion thereof, for storage that is not classified as a hazardous occupancy. 311.2 Moderate-hazard storage, Group S-1. Buildings occupied for storage uses that are not classified as Group S-2, including, but not limited to, storage of the following: • Aerosols, Levels 2 and 3 • Aircraft hangar (storage and repair) • Bags: cloth, burlap and paper • Bamboos and rattan

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59

• Baskets • Belting: canvas and leather • Books and paper in rolls or packs • Boots and shoes • Buttons, including cloth covered, pearl or bone • Cardboard and cardboard boxes • Clothing, woolen wearing apparel • Cordage • Dry boat storage (indoor) • Furniture • Furs • Glues, mucilage, pastes and size • Grains • Horns and combs, other than celluloid • Leather • Linoleum • Lumber • Motor vehicle repair garages complying with the maximum allowable quantities of hazardous materials listed in Table 307.1(1) (see Section 406.6) • Photo engravings • Resilient flooring • Silks • Soaps • Sugar • Tires, bulk storage of • Tobacco, cigars, cigarettes and snuff • Upholstery and mattresses • Wax candles 311.3 Low-hazard storage, Group S-2. Includes, among others, buildings used for the storage of noncombustible materials such as products on wood pallets or in paper cartons with or without single thickness divisions; or in paper wrappings. Such products are permitted to have a negligible amount of plastic trim, such as knobs, (Continued)

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Occupancy

handles or film wrapping. Group S-2 storage uses shall include, but not be limited to, storage of the following: • Asbestos • Beverages up to and including 16-percent alcohol in metal, glass or ceramic containers • Cement in bags • Chalk and crayons • Dairy products in nonwaxed coated paper containers • Dry cell batteries • Electrical coils • Electrical motors • Empty cans • Food products • Foods in noncombustible containers • Fresh fruits and vegetables in nonplastic trays or containers • Frozen foods • Glass • Glass bottles, empty or filled with noncombustible liquids • Gypsum board • Inert pigments • Ivory • Meats • Metal cabinets • Metal desks with plastic tops and trim • Metal parts • Metals • Mirrors • Oil-filled and other types of distribution transformers • Parking garages, open or enclosed • Porcelain and pottery • Stoves • Talc and soapstones • Washers and dryers

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Occupancy Classifications in Previous Building Codes

61

Utility and Miscellaneous Occupancies̶Group U Barns, greenhouses, private garages, and sheds are included in this category. In general, the Building Official’s judgment is used to determine what hazard such buildings represent and how they should be regulated.

2009 International Building Code SECTION 312 UTILITY AND MISCELLANEOUS GROUP U 312.1 General. Buildings and structures of an accessory character and miscellaneous structures not classified in any specific occupancy shall be constructed, equipped and maintained to conform to the requirements of this code commensurate with the fire and life hazard incidental to their occupancy. Group U shall include, but not be limited to, the following: • Agricultural buildings • Aircraft hangars, accessory to a one- or two-family residence (see Section 412.5) • Barns • Carports • Fences more than 6 feet (1829 mm) high • Grain silos, accessory to a residential occupancy • Greenhouses • Livestock shelters • Private garages • Retaining walls • Sheds • Stables • Tanks • Towers

OCCUPANCY CLASSIFICATIONS IN PREVIOUS BUILDING CODES Classification of building occupancy groups is as old as building codes themselves. As discussed in Chapter 3 of this book, codes were developed to reduce the chance of life and property loss in fires and were strongly influenced by multiple-fatality disasters. Occupancy groups were developed based on fire risk to occupants.

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Occupancy

For example, a theater with a legitimate stage and an occupant load of over 1000 people was historically classified as Occupancy Group A, the highest risk. A stage is defined in the code but has a high proscenium that can act as a shaft to convey fire through airflow through the building. An Occupancy Group B building, perceived as a slightly lower level of risk, may have a stage if the occupant load is less than 1000, or a high load but no stage. A large church might be a Group B building. Thus, the occupancy groups originally extended down the alphabet from A to J in order of decreasing risk to life. But with revision and refinement of codes, the names of individual occupancy groups changed repeatedly, so that a building department’s archived records may not be the same as the occupancy groups described earlier in this chapter. Examples of importance for historic buildings would be: 1. Occupancy Group F—This was historically the office occupancy. Many small and high-rise buildings used for offices will have this designation. Today, a Group F building would be a factory. 2. Occupancy Group H—Originally, the group for apartments and hotels, Occupancy Group H today indicates that hazardous materials and chemicals or processes are being conducted in the building. Today, hotels are included in Occupancy Group R-1, and apartment buildings are included in Occupancy Group R-2. 3. Occupancy Group I—This group designated one- and two-family dwellings in early codes. Today, such buildings are classified as Occupancy Group R-3, and an Occupancy Group I structure is an institutional building with many suboccupancies and safety requirements. Thus, records of an existing building may be misleading with respect to original occupancy groups. In some circumstances, original occupancy may be a desirable thing to know—for example, some codes and officials will permit a building whose occupancy has been changed to go back to its original use and occupancy. Such information may also help to predict structural and fire safety features that may be hidden from view, such as fireproofing of structural members and unusually heavy floor structures that would have been required in buildings designed for manufacturing. If questionable information about original occupancy emerges during the course of research, consult the original code under which a building was constructed.

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CHAPTER

7

Planning and Construction Factors

While occupancy, the building’s use, influences code requirements to a significant degree, several factors relating to characteristics of the building itself and its relationship to its environment also play a part in the code’s treatment of historic structures. Among these are siting, type of construction and materials, and the size of the building and its components.

SITING Siting is the relationship of a building to its lot, to its property lines, and to adjacent streets, sidewalks, and alleys. A building’s relationship to its site has a strong influence on its vulnerability to fire and on its healthfulness as an environment for occupants. Access to streets and alleys allows for operation, if needed, of emergency vehicles, such as fire apparatus and ambulances. And availability of exterior exit paths determines the ability of exiting occupants to disperse. The level of regulation varies by building occupancy type. For example, requirements for residential occupancies are less restrictive than those for offices or manufacturing.

Fire Concerns A major concern in siting is whether the building’s position and openings promote or retard the spread of fire to other structures. Such restrictions are among the oldest of building regulations, as the original perception of need for building codes dealt largely with preventing conflagrations. Historically, in an agrarian environment, buildings were too widely separated for fire spread between them to be a problem. But as early as medieval times, cities grew and became crowded, with buildings clustered together, often within a defensive city wall. Numerous conflagrations occurred in European cities, such as Amsterdam (1421 and 1452), London (1666), and Northampton (1675). 63

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Planning and Construction Factors

When cities were rebuilt, proponents of better building practices were often ignored, and the old hazards were reconstructed. The high value of city land meant that an owner’s short-term interest dictated use of the entire property, but the resultant crowding produced towns that might burn to the ground if a single building caught fire, as happened in the Great Chicago Fire. As modern cities developed, insurance companies and governments adopted regulations requiring a certain level of fire protection for buildings in business areas. One factor that was identified early as a contributor to conflagrations was crowding, which in practical terms meant inadequate distance between buildings. Thus, distance from a structure to property lines was one of the earliest characteristics regulated. Another such factor was construction materials of exterior walls, and the presence and construction of doors and windows. Early codes typically required solid masonry construction for these walls. If windows were permitted, steel sash with wire glass was required. Protection of structural elements from fire is regulated if they are within a specified distance of a property line. For example, combustible structural elements must be covered with protective material if they are within the regulated area. Siting may trigger requirements for parapets at the edges of roofs, as fire commonly spreads from roof to roof.

Health and Habitability Besides fire concerns, siting was important in the development of building regulations that endeavored to control the spread of disease, particularly tuberculosis. Incurable until the mid-twentieth century, tuberculosis was attributed to crowding and to lack of sunlight and ventilation. No doubt all these factors contributed to its spread. As cities developed with early multistory construction in the late nineteenth and early twentieth centuries, health issues became a factor in building regulation. To prevent the spread of disease, residential structures were required under tenement laws to provide natural light and ventilation. Even in nonresidential construction, natural light was desirable, because artificial light was inefficient and expensive. But providing light and ventilation via windows on the exterior walls conflicted with requirements for solid construction to prevent spread of fire. To solve this dilemma, architects created window wells near property lines, with windows at ninety degrees to the property line or set back a certain distance, permitting light and ventilation.

TYPE OF CONSTRUCTION AND MATERIALS Structural and architectural materials are important to regulating building hazard. In building design, materials must be considered at every level, beginning with the building’s structural skeleton, and continuing all the way, in some occupancies, to the choice of interior finishes.

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Type of Construction and Materials

65

Materials affect allowable setbacks and placement of a building on its site, practical span lengths, safe floor loading, time available for exiting, and many other characteristics of a building’s daily and emergency performance. Regulation of materials occurs at all levels of the code. However, in the case of existing structures, most of the materials are already in place. In historic buildings, many of these materials cannot be removed. In addition, materials and structural assemblies that were well known in their own time may have become archaic, and little information about their performance, capacities, and drawbacks may be readily available. In new construction, the desired use and location of the building typically drive the decision regarding which materials to use. In rehabilitation, the problem is turned on its head: the materials and location will strongly influence what the building can be used for. Within reason, code alternatives may be proposed to establish that existing materials will perform satisfactorily for a given use. Here, research regarding archaic materials is often invaluable; further discussion of this subject and of information sources is found later in this book. Materials considerations are important from the viewpoint of fire safety, structural performance, and health.

Type Construction Requirements Building codes classify construction types and materials in five general groups. Since the beginning of the construction classification system, the highest fire rating for a noncombustible building has been Type I construction. At the opposite end of the spectrum was Type V (commonly called “type 5”), which typically was wood frame construction. In regions of the United States that have used the Standard Building Code, Type VI construction is the same as the Type V discussed in this text. In between were Type II, Type III, and Type IV construction. Section 602 of the IBC summarizes construction classifications. Figure 7.1, IBC Table 601, provides

Figure 7.1 This table from the IBC shows the fire-resistance ratings for elements and all building types. © International Code Council

TABLE 601 FIRE-RESISTANCE RATING REQUIREMENTS FOR BUILDING ELEMENTS (hours) TYPE I

TYPE II

TYPE III

TYPE V

A

B

HT

Ad

b

1

0

1

0

HT

1

0

1

0

2

2

2

1

0

1

0

1

0

1/HT

1

0

A

B

A

g

Primary structural frame (see Section 202)

3

a

2

a

Bearing walls

3

2

Exteriorf, g

3a

2a

d

TYPE IV

B

BUILDING ELEMENT

d

Interior Nonbearing walls and partitions—Exterior a

See Table 602

Nonbearing walls and partitions—Interior

0

0

0

0

0

0

See Section 602.4.6

0

0

Floor construction and secondary members (see Section 202)

2

2

1

0

1

0

HT

1

0

Roof construction and secondary members (see Section 202)

1 ½b

1b,c

1b,c

0c

1b,c

0

HT

1b,c

0

See 2009 IBC for footnotes.

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Planning and Construction Factors

TABLE 602 FIRE-RESISTANCE RATING REQUIREMENTS FOR EXTERIOR WALLS BASED ON FIRE SEPARATION DISTANCEa,e FIRE SEPARATION DISTANCE ⴝ X (feet)

TYPE OF CONSTRUCTION

X < 5c

All

3

2

1

5 ≤ X < 10

IA

3

2

1

Others

2

1

1

IA, IB

2

1

1d

10 ≤ X < 30

X ≥ 30

OCCUPANCY OCCUPANCY OCCUPANCY GROUP GROUP H1 GROUP F-1, M, S-19 A, B, E, F-2, 1, R, S-29, Ub

IIB, VB

1

0

0

Others

1

1

1d

All

0

0

0

See 2009 IBC for footnotes.

Figure 7.2 Required fireresistance ratings for exterior walls. © International Code Council

the fire-resistance rating requirements for various building elements. Figure 7.2, IBC Table 602, provides the required fire-resistance rating for exterior walls.

2009 International Building Code SECTION 602 CONSTRUCTION CLASSIFICATION 602.2 Types I and II. Types I and II construction are those types of construction in which the building elements listed in Table 601 are of noncombustible materials, except as permitted in Section 603 and elsewhere in this code. 602.3 Type III. Type III construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by this code. Fire-retardant-treated wood framing complying with Section 2303.2 shall be permitted within exterior wall assemblies of a 2-hour rating or less. 602.4 Type IV. Type IV construction (Heavy Timber, HT) is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of solid or laminated wood without concealed spaces. The details of Type IV construction shall comply with the provisions of this section. Fireretardant-treated wood framing complying with Section 2303.2 shall be permitted within exterior wall assemblies with a 2-hour rating or less. Minimum solid sawn nominal dimensions are required for structures built using Type IV construction (HT). For glued-laminated members the equivalent net finished width and depths corresponding to the minimum nominal width and depths of solid sawn lumber are required as specified in Table 602.4. 602.5 Type V. Type V construction is that type of construction in which the structural elements, exterior walls and interior walls are of any materials permitted by this code.

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Type of Construction and Materials

67

The IBC uses a different approach for exterior wall protection than some earlier codes. The IBC will allow a percentage of the wall to have openings, depending on the distance of the wall to the property line. Typically, no openings are permitted less than 5 feet from the property line (see Figure 7.2). One always needs to read the footnotes to tables where there may be exceptions. Some of the reduction in property line wall fire-resistance requirements in the current codes comes from the greater reliance today on active systems, such as fire sprinkler systems, whereas the traditional code requirement was based on passive fire-resistance construction. Type I and Type II Construction In Type I construction, all building elements are of noncombustible materials. Type II is similar to Type I but with reduced fire protection on the structural members and reduced exterior wall protection. Type I construction is further divided into Type I-A and Type I-B. Type II has similar subdivisions. Structural steel and reinforcing steel lose strength under heat. Fire protection of the structural frame is intended to protect the concrete and steel and give fire suppression personnel time to suppress a fire. If the building is steel construction, the steel is covered with concrete, hollow clay tile, or other materials to provide fire protection. Historically, exterior walls were brick infill with terra cotta trim. Where brick was exposed on the exterior, it was a higher visual quality than “common” brick. As may be seen in Figure 7.1, the main difference between Types I and II is the fire protection of the structural frame and exterior bearing walls. Both Type I and Type II are of noncombustible construction. Type I requires a higher fire-resistance rating for the structural frame, bearing walls, and floor and roof construction. Type II-A requires fire-resistance ratings for the structural, bearing walls, floor and roof construction of a shorter time period, a lesser level of protection. Type II-B does not have any fire-resistance rating for these structural elements. Type I-A construction has unlimited height and area, except in a few uses. Type I-B is limited to 160 feet in height, with reduced height for certain uses. Type II-A buildings generally will have a height limitation of 65 feet and 55 feet for Type II-B. Historic high-rise buildings will generally meet the requirements of Type I construction. Type III Construction Type III construction is the typical “Main Street” building, the retail and office/ housing buildings that make up commercial districts. Historically, Type III buildings required solid 4-hour walls on the property line. To prevent the spread of fire between buildings, no openings were permitted in property line walls. The walls along the property lines of these older buildings are usually brick construction with no openings. Usually, such walls are 13 inches thick for a one- or two-story building and thicker when there are more stories. Later buildings may have concrete walls or concrete masonry block walls.

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Planning and Construction Factors

In these buildings, the floors and roof are usually wood joists with wood sheathing, usually two layers, with the bottom layer placed either straight or diagonally and with a finish layer of straight boards. Roofs of larger buildings are commonly structured with wood trusses, rafters, and sheathing. In smaller buildings, roof framing may be “carpenter trusses,” site-built trusses, spanning to the exterior bearing walls. In code language, Type III construction is that type of construction in which the exterior walls are of noncombustible construction and the interior building elements are of any material permitted by the code. In areas using the Standard Building Code, this would have been called a Type V building. In reality, some historic buildings may have openings on or near the property line. This may have resulted from a lot split or from construction prior to adoption of a building code. The IBC contains different criteria for windows near the property line, which may assist in dealing with walls near the property line.

Figure 7.3 Minimum sizes of timber to qualify as a Type IV building in the current IBC. © International Code Council

Type IV Construction Before the mid-1970s, construction classified as Type IV was all noncombustible. In the IBC, this is classified as Type II-B construction. It generally had light steel siding. Such buildings did not have any fire rating for the walls or structure. They had to be kept at least 5 feet from the property line. Historically, Type IV construction was used for small industrial and, in some cases, commercial buildings, including Quonset huts, which are now considered historic. In the 1976 UBC, the Type IV construction designation and fire rating criteria were changed to heavy timber (HT) construction. Today, Type IV construction has noncombustible exterior walls and solid or laminated timber interior members, called “heavy timber” in the code. Figure 7.3 shows the minimum dimensions of solid sawn and glue-laminated heavy timber members. In the IBC, Type IV construction is called heavy timber construction. Heavy timber is a minimum of 6-inch nominal thickness for beams and 8-inch nominal lumber for columns. Minor wood members may be 4-inch nominal. In older codes, a heavy timber building was classed as a Type III structure. The code anticipates that this type of construction will be open framing, and prohibits concealed spaces.

TABLE 602.4 WOOD MEMBER SIZE MINIMUM NOMINAL SOLID SAWN SIZE Width, Inch

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MINIMUM GLUED-LAMINATED NET SIZE

Depth, Inch

Width, Inch

Depth, Inch

8

8

6¾

8¼

6

10

5

10½

6

8

5

8¼

6

6

5

6

4

6

3

6 7/8

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Type of Construction and Materials

69

Type V Construction Wood frame buildings, typically houses, apartments, and small commercial buildings, are classed as Type V construction. Technically, structure and enclosure elements may be of any materials permitted by the code. Many historic buildings are of Type V construction, a potential source of code issues when an occupancy change is considered. A Type V building will usually have walls constructed of 2-inch wood studs, placed about 16 inches on center. The floors are typically wood joists, also spaced at 16 inches on center. The floors may have one or two layers of wood sheathing. The roof will be constructed of wood rafters spaced 16 to 24 inches on center, depending on the span length. Ceiling joists, which will form the floor of an attic, span to walls and have plaster or drywall on the bottom side. Ceiling joists are usually fairly light and not generally adequate to support floor-type loads. Wall finishes are plaster, drywall, or wood paneling. In some historic buildings, the roof is a very complex structure involving a hiptype roof with often irrational crossties. The spans of the rafters are much longer than can be calculated by normal engineering methods, but they stand up through a combined beam and arching action. Some of these definitions and requirements have changed over the years. Building owners may be surprised to discover that a current construction classification is different from the one on the original permit, even though the building has not changed.

Fire Concerns Fire safety concerns are the basis of many code requirements and limitations on construction materials. Depending on the type of construction and materials, there may be limitations on the type of occupancy permitted in a specific building construction type.

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Building codes regulate the height and size of buildings based on the type of construction. Codes permit larger buildings as potential for fire decreases. Historically, buildings of combustible construction were limited to three stories, since the maximum distance that a fire hose could pump water was about 45 feet.



Since the fire resistance of a building’s roof and exterior walls affects fire spread between buildings, building codes regulate exterior materials, often in conjunction with zoning codes.



Concrete and masonry have sufficient mass to resist a fire for a significant period.



Combustibility of structural materials and stairs is an important factor in firefighter safety, since firefighters will enter the building for rescue and to suppress the fire.

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Planning and Construction Factors



The building’s structural materials may contribute to the fire in some types of construction if they are combustible. In historic buildings, with no change of the type of occupancy, this is usually not an issue. However, in a change of occupancy, known as adaptive reuse, building construction requirements may be a design issue when the new occupancy has different fire separation requirements between uses as well as requirements of materials and finishes.



Steel requires fire protection because it loses strength under heat. In late nineteenth-century and early twentieth-century buildings, steel was encased with concrete for fire protection. Later, asbestos and other materials were used. As noted in the discussion of types of construction, many historic buildings had a higher level of fire protection than would be required for new buildings today.



The flame-spread potential of interior finishes influences both smoke generation and the speed of fire spread along walls, ceilings, and corridors. With experience of life loss in fires, requirements for flame-spread rating have increased. Formerly unregulated building areas, such as interior office spaces, must now meet flame-spread requirements. Corridors in historic buildings may be finished with wood paneling or wainscot, which may become a code issue. There have been many solutions or compromises for these situations. An example may be to apply an intumescent coating over existing wood paneling. Another is to install fire sprinklers to provide a reasonable level of safety.



Some noncombustible materials, such as marble stair treads and cast iron columns, may deform or fracture due to heat. This can influence both occupant exiting and firefighter safety. Current codes may require fire protection under stairs.



The materials and construction of doors will influence how quickly a fire will spread from the compartment of origin. Interior glazing and transoms may hasten the spread of a fire through a building, and cause quick involvement of the exitways, substantially reducing time available for exiting. Historic buildings often had transoms over corridor doors as well as glass or grilles in doors. Each of these provides a vehicle for the spread of smoke and fire. Past solutions have included applying metal or gypsum board over glazing in corridor walls. More recently, special sprinkler heads have been used to reduce the risk.

Structural materials are chosen to bear the loads imposed on them in a building’s original occupancy. But some materials have changed. For example, wood has been allowed in the past in buildings constructed for use as factories, but wood members of acceptable size and quality are no longer available. Manufactured wood products, such as glue-laminated beams, are now used. However, the old wood members were, and remain, competent to carry the loads. Structural steel that was fabricated before the mid-1950s may have less strength than steel in use today, and may require special preparation if welding is proposed.

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Building and Component Size

71

This is important if the floor load capacity or seismic safety require improvement. Archaic materials, such as cast iron, may be acceptable, but if new loads are added, structural evaluation may be necessary.

Health and Habitability General health and safety requirements that affect type of construction include those code provisions pertaining to glazing and shafts. As building codes evolve, they have reflected the identified needs for improved safety. Plate glass has been identified as a safety hazard for many years. It breaks into large jagged pieces with sharp points and edges. Injuries and deaths have resulted from plate glass breakage. As building design changed, more glass was used, for example, sliding glass doors leading to patios and decks. Not infrequently, people walked into such doors, or children ran into such doors, resulting in injuries. The U.S. Consumer Product Safety Commission (CPSC) established requirements for areas needing safety glazing. Glass located within 18 inches of a floor surface is required to be laminated or tempered. Safety glazing is required under other conditions and locations also. This has been modified over time and is now included in the building code. Later in this book, we discuss the provisions of codes that require safety glazing when glass is replaced in such locations. The fire-resistive construction of shafts, including those used for stairways, ventilation ducts, and pipe chases, has become more restrictive as experience has shown how fires spread throughout a building.

BUILDING AND COMPONENT SIZE Building design includes an important component of artistry, but the rest is scientific and mathematical. From the sizing of structural elements to determining acceptable exit widths, calculations affect both large and small decisions. As with other code provisions, these calculations are used in a synthesis process when a building is designed. In building rehabilitation, there is a combination of analysis and synthesis. The building’s major design is complete, and many of the building and component sizes are fixed: height, area, size of rooms, width of corridors and stairs—all are in place and are hard, often impossible, to modify, particularly if they have architectural or historic value. Only two other possibilities exist: to modify occupancy choice, thus changing the rules; or to develop alternatives, as discussed later in this book, to make the building work in its existing form with little modification. Often, occupancy choice is out of the hands of the designer, so the project can be made to work only if acceptable alternatives can be developed. The first step in the development of alternatives is to understand the rules and the reasons for them. Sizing influences factors including fire safety, structural safety, and general health and accessibility features.

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Fire Concerns The height of a building influences accessibility for firefighting. Direct access via ladder truck is possible only within the first 55–75 feet of building height. Building height may determine acceptable materials of construction. For example, the code limits the height of combustible construction (wood) and requires protection of other materials, such as steel, in taller buildings. The plan dimensions of a compartment also influence accessibility for firefighting. Where exterior openings exist on only one side, and these openings are more than 75 feet from the opposite wall, access for firefighting from the exterior is limited. Such buildings are required to have automatic sprinkler systems. Stairs are traversed more slowly than level exitways. For this reason, egress width for stairs is required to be greater than that for exit level exitways. Dimensions of stair treads and risers are prescribed to limit the steepness of stairs so that they may be traversed as quickly as possible. Minimum distance between exits, either from a compartment or from a building, is prescribed to limit the likelihood that a single fire can block multiple exits. Maximum travel distance to an exit is prescribed by occupancy and is also affected by the presence of a sprinkler system. Maximum length of dead-end corridors is specified to avoid entrapment of occupants under fire conditions. Egress width is calculated based on occupant density for the assigned occupancy, multiplied by the area of the compartment or building. Minimum width of exitways is intended to provide for occupants walking two abreast, except where fewer than fifty occupants are served by the exitway. Structural span and materials will be influenced by the height of the structure, floor loads, and economics.

Health and Habitability Wheelchair-accessible means of egress or safe wheelchair holding areas (areas of refuge) are required to be provided in certain occupancies. Tactile signs, graspable handles and railings, visibility stripes on the leading edge of stairs, and alarms that are both visible and audible are many examples of code changes that allow buildings to be accessible to all persons. A minimum size is required for habitable rooms. Such rooms, defined variously, generally include nonutility spaces in residential occupancies. The concept of minimum room size is a legacy of the New York Tenement Acts of the nineteenth century and is embodied in most regulations with the Housing Code developed by the American Public Health Association (APHA). Control of stair riser and tread sizes, in addition to facilitating exiting, reduces the likelihood of falls on stairs. Recent code changes have changed the maximum rise of stairs. Guardrail heights are specified to reduce the risk of falls. Code changes over the years have increased guardrail height, while the spacing of balusters has decreased.

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PART

4

HOW CODES REGULATE EXISTING BUILDINGS

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CHAPTER

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Principles of Regulating Existing Buildings

Building codes have always had to deal with the existing stock of buildings. In most cases, the regulations have permitted existing buildings to remain and to continue to be used, usually without mandating any changes.

2009 International Building Code SECTION 102.6 EXISTING STRUCTURES The legal occupancy of any structure existing on the date of adoption of this code shall be permitted to continue without change, except as is specifically covered in this code, the International Property Maintenance Code or the International Fire Code, or as is deemed necessary by the building official for the general safety and welfare of the occupants and the public.

Occasionally, a jurisdiction will require that buildings of a certain occupancy or construction type be rehabilitated in specific ways. An example of this would be exit enclosures for multistory apartments and hotels. Another would be seismic strengthening of unreinforced masonry buildings in high-risk areas. However, retroactive requirements are the exception, not the rule. Retroactive requirements may be enforced if a specific building type or occupancy is deemed to be unsafe by the jurisdiction. This is an involved legal process that pits the individual’s property rights against the rights of the community in general. Earlier discussion on building codes described the constant updating based on various reasons. Section 102.6 is an example. Minor detail changes, added or clarified provisions, and new requirements and materials all occur. This book considers the provisions of the 2006 and 2009 editions of the International Codes family. For the International Existing Building Code, provisions of the 2006 and 2009 editions are shown. Some changes from the 2012 edition of the IEBC are noted, but that code was not complete during the preparation of this book. 75

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WHAT DO YOU NEED TO KNOW ABOUT YOUR BUILDING? To understand what building code requirements may be applicable to a historic building, an owner or designer needs to have a fundamental knowledge of the structure. Specific information needed includes the following. Legal information: This includes the address, legal description, and, in most areas, the assessor’s parcel number. Often, the assessor’s records will lead to information about the building history. Historic designation: Is the building officially designated on the National Register, State Register, or local landmarks list? If not, is it a contributing structure to a historic district? Depending on the state or locality, being listed in a survey may be adequate for historic code provisions. Even if a building is not designated, it is important to know whether it is eligible for listing. Building permit history: Review of permit records for the building will provide much of the information needed. Buildings are issued a certificate of occupancy, often called a “C of O.” This will usually provide considerable information about the building, including additions and major alterations. Building occupancy category information: Review records for the historic occupancy group designation as well as the current occupancy group. In some locations, there may be a right to restore the building to its occupancy at the time of the original construction. Building construction type: The type of construction, as denoted by the building code, will assist you in understanding the material and component size requirements. A better understanding of construction type may involve looking behind finishes or in unfinished locations. Although major structures are commonly Type I construction, the majority of smaller buildings are either wood frame (Type V) or masonry wall (Type III) construction. Zoning and other regulations: Other regulations, not in the building code, may have an effect on a historic building project. Agencies such as the planning department or the community redevelopment agency should be investigated. Existing buildings have what are called “nonconforming” rights. This is discussed later in this chapter. Much of the building information may be obtained from existing records and documents.

BUILDING REHABILITATION AND REGULATION Normally, unless an existing building is undergoing work for which a building permit is required, it does not need to meet current codes. However, once such work is planned, code issues should be considered from the beginning. In the 2009 International Building Code, work on existing buildings is regulated by Chapter 34.

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Additions to a building must conform to the code for new construction and must not cause the building to violate current restrictions on height and area. Load increases, if any, on existing structural members must be shown to be in conformance with the code. Alterations that add structural loads to a building must be shown to conform to requirements for new construction, or an engineering analysis must be submitted to show that the performance of the building will be adequate. Nonstructural elements used in alterations are generally permitted to be made of the same materials as those of the original building but must not reduce fire performance or structural strength. When existing stairways are altered or replaced, they are not required to conform to current code provisions regarding rise and run of stairs if the existing space does not permit such a change in dimensions. If a change of occupancy is involved, requirements increase. The code’s approach is to avoid creating new hazards. Thus, if it can be shown that, although the building does not conform to the code in every respect, it is actually less hazardous in the new use than in the existing use, the change of occupancy would be permitted.

2009 International Building Code SECTION 3408 CHANGE OF OCCUPANCY 3408.1 Conformance. No change shall be made in the use or occupancy of any building that would place the building in a different division of the same group of occupancies or in a different group of occupancies, unless such building is made to comply with the requirements of this code for such division or group of occupancies. Subject to the approval of the building official, the use or occupancy of existing buildings shall be permitted to be changed and the building is allowed to be occupied for purposes in other groups without conforming to all the requirements of this code for those groups, provided the new or proposed use is less hazardous, based on life and fire risk, than the existing use. 3408.2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met. 3408.3 Stairways. Existing stairways in an existing structure shall not be required to comply with the requirements of a new stairway as outlined in Section 1009 where the existing space and construction will not allow a reduction in pitch or slope. 3408.4 Change of occupancy. When a change of occupancy results in a structure being reclassified to a higher occupancy category, the structure shall conform to the seismic requirements for a new structure of the higher occupancy category. Where the existing seismic force-resisting system is a type that can be designated ordinary, (Continued)

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values of R, Ω0 and Cd for the existing seismic force-resisting system shall be those specified by this code for an ordinary system unless it is demonstrated that the existing system will provide performance equivalent to that of a detailed, intermediate or special system. Exceptions: 1. Specific seismic detailing requirements of this code or Section 1613 for a new structure shall not be required to be met where it can be shown that the level of performance and seismic safety is equivalent to that of a new structure. Such analysis shall consider the regularity, over strength, redundancy and ductility of the structure within the context of the existing and retrofit (if any) detailing provided. 2. When a change of use results in a structure being reclassified from Occupancy Category I or II to Occupancy Category III and the structure is located in a seismic map area where SDS < 0.33, compliance with the seismic requirements of this code and Section 1613 are not required.

Under the International Building Code and the International Existing Building Code, historic structures are granted some special exceptions. However, if a historic building is hazardous, it would be required to be repaired.

2009 International Building Code SECTION 3409 HISTORIC BUILDINGS 3409.1 Historic buildings. The provisions of this code relating to the construction, repair, alteration, addition, restoration and movement of structures, and change of occupancy shall not be mandatory for historic buildings where such buildings are judged by the building official to not constitute a distinct life safety hazard. 3409.2 Flood hazard areas. Within flood hazard areas established in accordance with Section 1612.3, where the work proposed constitutes substantial improvement as defined in Section 1612.2, the building shall be brought into conformance with Section 1612. Exception: Historic buildings that are: 1. Listed or preliminarily determined to be eligible for listing in the National Register of Historic Places; or 2. Determined by the Secretary of the U.S. Department of Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined to qualify as an historic district; or 3. Designated as historic under a state or local historic preservation program that is approved by the Department of Interior.

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Alternatives to code provisions are at least partially a matter of judgment, since the relationship between the factors that produce safety or hazards in a building— occupancy, siting, materials of construction, and building/component size—react with one another in complex ways that are never entirely quantifiable. The means of developing alternatives to code provisions are discussed elsewhere in this book.

NONCONFORMING RIGHTS One of the most important concepts in working with codes and existing buildings is the concept of nonconforming rights. Stated simply, the concept establishes that conditions in existing buildings that are nonconforming but not hazardous are probably acceptable. While simple enough in theory, nonconforming rights can be puzzling and seemingly contradictory. For example: 

If a stair in an existing building is somewhat steeper than would be permitted in new construction, it would probably be accepted to leave the nonconforming stairs in place. But the owner would not be permitted to construct a matching stair elsewhere in the building.



If a building is slightly structurally overloaded, based on today’s standards, it might be accepted, but a designer would not be permitted to overload a conforming existing building with new loads in exactly the same amount.



If a building is slightly larger in area than would be currently permitted for its previously approved occupancy, it might be deemed acceptable. But a new addition that would result in a conforming building becoming too large in area would not be approved.



If a building does not precisely conform to requirements for its occupancy, it would be permitted to continue in that occupancy if it did conform at the time it was constructed, provided that the nonconformity is not considered a significant hazard. But a hypothetical twin building of another use might not be permitted to change to the occupancy of the first.

The reason for this apparent incongruity is the previously discussed principle that building laws are not applied retroactively unless it is necessary to alleviate serious hazards. However, even in work on an existing building, the creation of new conditions—new physical features, new occupancy, new loads—does not qualify for nonconforming rights.

CHANGE OF OCCUPANCY Nothing stands still. Times change, and neighborhoods, buildings, needs, and codes change with them. A textile mill closes, shuttering a building that was the mainstay of a town for a hundred years. A street of historic houses, once a fashionable neighborhood, becomes derelict. A neighborhood church loses its congregation. A school

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must move to a structure that complies with seismic regulations, abandoning its historic structure. Buildings, like communities and individuals, must survive on an economic level. For these buildings to continue to exist, they must meet new needs—as housing, libraries, offices, community centers, and, rarely, museums. But, unless the new use is similar to the old or is associated with fewer hazards and regulations, a historic building may be all but lost in the process of saving it. At the very least, a designer should expect serious scrutiny concerning possible hazards in the new occupancy and should be prepared to acknowledge and provide for safety needs, either by meeting the requirements of the code or by providing wellconsidered, competently designed alternatives to it. In rehabilitation of historic buildings, occupancy choice is one of the major determinants of success or failure. In Chapter 6, occupancy and its building code definition were explored, including reasons for regulating occupancy and the ways in which codes attempt to address hazards due to building use. When the occupancy of a building changes, the building may partially or completely lose nonconforming rights. Codes are usually flexible with regard to occupancy change but not to the point of allowing new hazards to be created. Some approaches rely on the judgment and experience of code officials to determine what is acceptable; others use classification and quantification in an attempt to standardize the occupancy change process. The International Existing Building Code provides a choice of several approaches to code compliance, each with its own mixture of subjective and objective criteria. Particularly for projects involving occupancy change, a careful study of possible benefits and drawbacks of each approach is recommended.

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CHAPTER

9

International Existing Building Code Compliance Methods

WHY USE THE INTERNATIONAL EXISTING BUILDING CODE? The IEBC is one of a family of codes published by the International Code Council (ICC). The IEBC provides a rehabilitation code that can be used comfortably by building departments across the country. Often in rehabilitation, building department personnel are concerned about liability if they permit anything that is not in full compliance with the code for new construction. The IEBC provides the “standard of care” that the regulatory and the design community desires.

HOW IS THE IEBC ORGANIZED? The IEBC offers three compliance methods for work on existing buildings: the Prescriptive Compliance Method, Chapter 10 in this book; the Work Area Compliance Method, Chapters 11 and 12 in this book; and the Performance Compliance Method, Chapter 13 in this book. Figure 9.1 shows graphically the location of the three compliance methods in this book and in the IEBC. IEBC Compliance Methods Chapter 9

Prescriptive Compliance Method Chapter 10 (IEBC Chapter 3)

Work Area Compliance Method Chapters 11 & 12 (IEBC Chapters 4–12)

Performance Compliance Method Chapter 13 (IEBC Chapter 13)

Figure 9.1 The International Existing Building Code provides three methods to achieve compliance. This chart shows the location in this text where each of these methods, and their provisions, are discussed. © Melvyn Green

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Each method offers a different approach and flexibility for both the design professional and the building official. It is important to choose the one that best matches the needs of the project. The various chapters are arranged as follows: Chapter 1—Administrative Chapter 2—Definitions Chapter 3—Prescriptive Compliance Method Chapters 4–12—Work Area Compliance Method Chapter 13—Performance Compliance Method Chapter 14—Construction Safeguards Reference: Standards Appendix A—Guidelines for the Seismic Retrofit of Existing Buildings Appendix B—Supplementary Accessibility Requirements of Existing Buildings and Facilities Resource A—Guidelines on Existing Fire Ratings of Archaic Materials and Assemblies Within Chapters 1 and 2 are several sections and definitions that are particularly important. Section 101.5 provides for the selection of the Compliance Method.

Building codes are typically updated on a three-year cycle. This permits changes based on experience and allows new approaches to be incorporated in the code. The IEBC is updated in a similar cycle. This text is based on the 2006 IEBC and also includes provision changes from the 2009 edition. Text excerpts, including those from the 2012 editions of the IBC and IEBC, are based upon the most up-to-date wording at the time of printing. Users should be careful to note the edition of quoted code provisions. Starting in 2009, the IBC and IEBC use italicized text to indicate terms that are defined in Chapter 2 of each edition. Italicized text within the code should be reviewed as it usually is used to clarify terms. Also note that code changes are demarcated with vertical bars in the margin beside the new text in each edition. An explanation of markings is found in the preface of each code edition.

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The 2012 IEBC rearranges information within its chapters. Introductory information on compliance methods has moved from Chapter 1 to a new Chapter 3.

2012 International Existing Building Code Chapters Chapter 1—Administrative Chapter 2—Definitions Chapter 3—Compliance Methods Chapter 4—Prescriptive Compliance Method Chapters 5–13—Work Area Compliance Method Chapter 14—Performance Compliance Method Chapter 15—Construction Safeguards Chapter 16—Reference Standards

2009 IEBC Section 101.5 Compliance methods. The repair, alteration, change of occupancy, addition or relocation of all existing buildings shall comply with one of the methods listed in Sections 101.5.1 through 101.5.3 as selected by the applicant. Application of a method shall be the sole basis for assessing the compliance of work performed under a single permit unless otherwise approved by the code official. Sections 101.5.1 through 101.5.3 shall not be applied in combination with each other. Where this code requires consideration of the seismic-force-resisting system of an existing building subject to repair, alteration, change of occupancy, addition or relocation of existing buildings, the seismic evaluation and design shall be based on Section 101.5.4 regardless of which compliance method is used. Exception: Subject to the approval of the code official, alterations complying with the laws in existence at the time the building or the affected portion of the building was built shall be considered in compliance with the provisions of this code unless the building is undergoing more than a limited structural alteration as defined in Section 807.5.3. New structural members added as part of the alteration shall comply with the International Building Code. Alterations of existing buildings in flood hazard areas shall comply with Section 601.3. 101.5.1 Prescriptive compliance method. Repairs, alterations, additions and changes of occupancy complying with Chapter 3 of this code in buildings complying with the International Fire Code shall be considered in compliance with the provisions of this code. 101.5.2 Work area compliance method. Repairs, alterations, additions, changes in occupancy and relocated buildings complying with the applicable requirements of Chapters 4 through 12 of this code shall be considered in compliance with the provisions of this code. 101.5.3 Performance compliance method. Repairs, alterations, additions, changes in occupancy and relocated buildings complying with Chapter 13 of this code shall be considered in compliance with the provisions of this code.

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2009 IEBC Section 101.5.4 Seismic Loads No building constructed under any code is “earthquake proof.” High levels of seismic resistance can be achieved in new construction, but the economic and functional costs are higher than is generally considered acceptable. No one wants to design an office building like a nuclear reactor, and no one would want to work in such a building if it existed. Many common activities, such as driving a car, flying in an airplane, or participating in sports, involve a certain risk level. Seismic safety in buildings is no different. Some risk is inevitable, but codes must define and enforce a reasonable level. “Life safety,” a term commonly used, is strongly promoted but not easily defined. Does “life safety” mean that not one person in any building could be killed in an earthquake? Does it mean that casualties will be low, but that some are tolerable? What about property safety? Even if deaths and injuries could be eliminated, financial loss and loss of infrastructure are significant problems. How far should a code go to minimize them? Should life and property safety be concerned with occupancy? These are serious questions with far-reaching consequences. Structural engineers and building code officials have debated the appropriate level of upgrade and repairs for existing buildings for many years. Codes dating back to the mid-1990s will provide for structural life safety. Each succeeding code has changed requirements that reduce the amount of property damage. In the 2009 edition of the IEBC, Chapter 1 clarifies the type and level of seismic forces to be used for an evaluation. The specific criteria depend on the (Seismic Design) Occupancy category. The prescriptive compliance method contains extensive structural evaluation provisions. The work area method has similar provisions. In all probability, a similar approach will be added to the performance compliance approach in time. Grappling with seismic hazards and reasonable levels of risk is an ongoing issue and is likely to be so for some time to come. Resources for evaluation and rehabilitation of buildings are available through the Federal Emergency Management Agency (FEMA) and the American Society of Civil Engineers (ASCE).

In the 2012 IEBC, Section 101.5 Compliance Methods is moved without content change to a new Chapter 3 entitled Compliance Methods.

2012 International Existing Building Code SECTION 301 COMPLIANCE METHODS 301.1 General 301.1.1 Prescriptive compliance method 301.1.2 Work area compliance method 301.1.3 Performance compliance method

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Alternate Materials and Methods Building codes acknowledge that new products and methods will be developed. To allow for alternate methods and new materials, both the IBC and the IEBC furnish procedures for acceptance of alternates. Since many products used in historic and other existing buildings are no longer used, information about these materials has been difficult to find until recently with the HUD Rehabilitation Guideline series, Resource A of the IEBC, and web search techniques. An example is the use of hollow clay tile (HCT) for fire protection, fire walls, and, in some cases, structural walls. For the most part, this material is not used today. Fire walls are constructed of gypsum board or similar material. The IEBC contains a chapter titled Resource A, which provides the fire-resistance rating for HCT and other materials. Another aspect of alternative materials is the use of “operational controls.” Operational controls are changes in the way the building is operated, which were instituted to improve safety. For example, if a stairway to a second floor is of inadequate width or the only stairway, an operational control would be to limit the occupancy above the first floor to the capacity of the exit system, in this case less than ten persons at a time. This is an operational control and whether it meets the standard of alternative materials and methods has been debated with no firm agreement.

2009 IEBC Section 104.11 Alternative materials, design and methods of construction, and equipment. The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design, or method of construction shall be approved where the code official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method, or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability, and safety.

Plan Requirements When proposing a construction project, it is necessary to provide sufficient plans to permit determination of compliance. These are called construction documents. Typically, construction documents would show a plot plan, floor plans and elevations, the exit system, and the details of wall assemblies. Depending on the specific project, the plans may include electrical, mechanical, and structural plans. Means of egress is always important in rehabilitated buildings. The IEBC requires that the exit system and its corridors, stairs, and doors be clearly shown on the plans.

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2009 IEBC Section 106.2.3 Means of egress. The construction documents for Alterations–Level 2, Alterations–Level 3, additions, and changes of occupancy shall show in sufficient detail the location, construction, size, and character of all portions of the means of egress in compliance with the provisions of this code. The construction documents shall designate the number of occupants to be accommodated in every work area of every floor and in all affected rooms and spaces.

Before a building may be occupied, a certificate of occupancy (C of O) is required. It establishes the right of the specific use in the building. The C of O is issued by the Building Official. See Section 110.1, 2009 IEBC.

110.1 Altered area use and occupancy classification change. No altered area of a building and no relocated building shall be used or occupied, and no change in the existing occupancy classification of a building or portion thereof shall be made until the code official has issued a certificate of occupancy therefore as provided herein. Issuance of a certificate of occupancy shall not be construed as an approval of a violation of the provisions of this code or of other ordinances of the jurisdiction.

Several definitions in Chapter 2 are very important. Not uncommonly, contractors, inspectors, and lay people carelessly describe a building as “dangerous.” The sole basis for such a judgment may be observation of superficial deterioration rather than a technical investigation. And historic buildings may be overgrown with plants or simply very dirty. However, a deteriorated building is not necessarily dangerous. The IEBC contains specific engineering evaluation criteria that will determine if the structure is dangerous in accordance with the building code. Even if an element is determined to be dangerous, it is probably repairable. The specific definition is shown below. Here is a side-by-side comparison of the definition of “dangerous” between the 2006 IEBC and the 2009 IEBC. The definition in the 2006 edition had been in use for many years. Specific engineering analysis was used in defining “dangerous.” The 2009 edition has eliminated the objective approach in favor of one that might be more subjective and offers little guidance to the building official and the user.

2006 IEBC—DANGEROUS. Any building or structure or any individual member with any of the structural conditions or defects described below shall be deemed dangerous: 1. The stress in a member or portion thereof due to all factored dead and live loads is more than one and one third the nominal strength allowed in the International Building Code for new buildings of similar structure, purpose, or location.

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2. Any portion, member, or appurtenance thereof likely to fail, or to become detached or dislodged, or to collapse and thereby injure persons. 3. Any portion of a building, or any member, appurtenance, or ornamentation on the exterior thereof is not of sufficient strength or stability, or is not anchored, attached, or fastened in place so as to be capable of resisting a wind pressure of two thirds of that specified in the International Building Code for new buildings of similar structure, purpose, or location without exceeding the nominal strength permitted in the International Building Code for such buildings. 4. The building, or any portion thereof, is likely to collapse partially or completely because of dilapidation, deterioration or decay; construction in violation of the International Building Code; the removal, movement or instability of any portion of the ground necessary for the purpose of supporting such building; the deterioration, decay or inadequacy of its foundation; damage due to fire, earthquake, wind or flood; or any other similar cause. 5. The exterior walls or other vertical structural members list, lean, or buckle to such an extent that a plumb line passing through the center of gravity does not fall inside the middle one third of the base. 2009 IEBC—DANGEROUS. Any building, structure or portion thereof that meets any of the conditions described below shall be deemed dangerous: 1. The building or structure has collapsed, partially collapsed, moved off its foundation or lacks the support of ground necessary to support it. 2. There exists a significant risk of collapse, detachment or dislodgment of any portion, member, appurtenance or ornamentation of the building or structure under service loads.

For a structure to qualify for the special provisions applicable to historic structures, the IEBC, as well as the IBC, define what constitutes such structures. For code purposes the structure must be designated in accordance with the following section. Various state laws, including environmental regulations, may permit buildings identified as “potentially eligible for listing” to be regulated by a code such as the IEBC.

2009 IEBC—HISTORIC BUILDING. Any building or structure that is listed in the State or National Register of Historic Places; designated as a historic property under local or state designation law or survey; certified as a contributing resource within a National Register listed or locally designated historic district; or with an opinion or certification that the property is eligible to be listed on the National or State Register of Historic Places either individually or as a contributing building to a historic district by the State Historic Preservation Officer or the Keeper of the National Register of Historic Places.

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The IEBC has a definition of the term “technically infeasible.” The intent of this definition is to provide a vehicle for consideration of alternatives when applying the provisions for accessibility to existing buildings. Many accessibility improvements that are intended to comply with applicable new construction requirements may require extreme effort and removals due to existing physical conditions. The code uses this as a basis for consideration of exceptions.

2009 IEBC—TECHNICALLY INFEASIBLE. An alteration of a building or a facility that has little likelihood of being accomplished because the existing structural conditions require the removal or alteration of a load-bearing member that is an essential part of the structural frame or because other existing physical or site constraints prohibit modification or addition of elements, spaces, or features that are in full and strict compliance with the minimum requirements for new construction and that are necessary to provide accessibility.

PRESCRIPTIVE COMPLIANCE METHOD The prescriptive compliance method is the traditional code approach that has been used for many years. Building code enforcement officials are usually familiar with this approach, as are many design professionals. The following suggestions should help in using the prescriptive compliance method:

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Scheduling a meeting early in the design process to review the project with the building department is very helpful. Understanding the approach that the department takes in regulating existing buildings will permit the design phase to proceed as smoothly as possible. Additional meetings during the design phase will be desirable for many projects.



During design, recognize that the project is a team effort. Considering only architectural issues, such as fire safety, without understanding the structural issues may result in incomplete understanding of the design needs. Treat the building department as part of the team.



Understand the issues with the building. Do your homework to understand the building and the code issues before the first meeting. Never ask the building department, “What do I have to do?” or “What do you want me to do?” Propose a direction you deem appropriate for the project.



You may require an alternate method to solve a particular issue. Understand the reason for the applicable provision so that method of compliance can be developed to meet the code’s intent.



An issue with the prescriptive compliance method is that, until you develop the project to a specific level, it is very difficult to estimate project construction costs.

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WORK AREA COMPLIANCE METHOD The work area compliance method is a new concept in codes. Its intent is to clearly define the limits and intent of the work to improve predictability of development requirements and hence project costs. The designer must clearly define the area of work as well where incidental work may be required. Work area as defined in the IEBC is as follows.

2009 IEBC—WORK AREA. That portion or portions of a building consisting of all reconfigured spaces as indicated on the construction documents. Work area excludes other portions of the building where incidental work entailed by the intended work must be performed and portions of the building where work not initially intended by the owner is specifically required by this code.

In using this approach, the designer must clearly understand the code provisions, which takes careful reading of the code since the requirements of each chapter build on those of the previous chapter. Understanding the reason for code requirements will permit effective use of this method. The work area method does not require a lot of judgment by the building department, since most of the requirements are clearly spelled out. But each building is different and there are always unique issues.

PERFORMANCE COMPLIANCE METHOD The performance compliance method uses a completely different system for evaluation and upgrading of the building. This method reviews all the fire and safety features of the building and uses a point or score approach to determine the adequacy of the building’s fire and life safety systems. It requires a careful evaluation of all of the building’s life safety and fire protection systems. This may be the best approach when 

A general review of alternatives in the entire building life safety system, official or for in-house design purposes, is needed.



A change of occupancy is being considered.



The building department sees few adaptive use or rehabilitation projects.



Completion of the performance compliance study and bringing the building up to minimum standards will permit most future alterations to be undertaken with minimum code complications.

The structural safety parameter of this method is somewhat confusing because it specifies full compliance with the IBC. The IBC may be interpreted as sending the designer to Chapter 34, Existing Buildings, and doing this triggers a requirement to use the prescriptive compliance approach for the structural work. The provisions

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require full compliance with the live loads under the current code. Repairs and other building systems are not addressed. There is no procedure for alternative methods in the provisions, but the IBC alternate materials and methods process could be requested. Because the performance compliance method highlights the fire and life safety issues, it may be helpful to use it as an in-house design tool, even when another compliance method is chosen for official use.

EXAMPLE BUILDINGS In the following chapters are several example applications of each of the three methods. The same buildings are used to illustrate each compliance method and are described below.

EXAMPLE BUILDING

1

On the “Main Street” of most communities are small historic buildings, typically one or two stories in height. The first floor may have a retail or business use; the second may be offices or housing. Such buildings typically extend from the street to an alley at the rear. As an example, we will consider a typical 1910–1930 one-story building of this type. The example building’s occupancy, typical of such structures, is a retail store, with sales area in the front and a restroom in the back for employees. Figure 9.2 is a typical “Main Street” found in many towns and cities.

Figure 9.2 Typical block of buildings found in most communities. © Melvyn Green

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Figure 9.3 Plan view of Example Building 1, a lowrise building typical of many downtown commercial areas in cities across the United States. © Melvyn Green

Figure 9.4 The older business district in a community. Buildings are mostly one- and two-story brick structures. © Melvyn Green

The example building is one story, 25 feet wide by 100 feet deep, giving a gross area of 2500 square feet. The building’s height is 15 feet to the roof. Figure 9.3 is a plan view of the building. Figure 9.4 is an example of the façade of a building of this type. Figures 9.5 and 9.6 show other buildings and details that might be found in a typical older business district. In many parts of the country, such buildings typically have basements, but this example does not. The building has a concrete foundation. The floor slab on grade is concrete. The side property line walls are unreinforced clay brick firewalls with no openings. The rear elevation is also brick with a toilet room window and a steel door at the alley. The first-floor façade is wood construction with glass show windows and a glazed wood door. Above the show windows is brickwork supported by a steel beam.

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Figure 9.5 Another example of a late nineteenth-century business district. Before building codes, many of the buildings had wood property line walls. When entire cities burned, these walls did nothing to stop the spread of fire. © Melvyn Green

Figure 9.6 A typical storefront. Display windows are right on the street front with a recessed door. This is typical of the example building used in this book. © Melvyn Green

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The roof is flat, with a parapet around its full perimeter. Roof framing consists of small trusses spaced at 24 inches on center, spanning from side wall to side wall. At the time the building was constructed, this was called Type III construction. In today’s codes, it is Type III-B. The interior space is open with no partitions except for a small toilet room. The interior side of the brick side walls are plastered, as are the partitions. The ceiling is wood lath and plaster construction. Lighting consists of fluorescent fixtures hanging from the ceiling. The original fixtures were incandescent, but those were removed in a remodeling in the early 1970s. The electrical service is minimum, 50 amps. The original building had no mechanical heating or air conditioning. A gas furnace was installed at the same time as the fluorescent lights. Possible code issues with this building are the width of the front and rear doors as well as the direction of the swing of the doors. The toilet room is small, and accessibility requirements need to be considered. Since accessibility requirements vary from state to state, the designer must consult state regulations as well as the IEBC, taking into account whether the building is officially listed as historic.

Most urban centers have one or more high-rise buildings constructed in the period from 1910 to 1930. These buildings vary from six to fifteen or more stories. Many remain today as important elements of cities’ traditional streetscapes. They may be designated historic structures. Sometimes these buildings have high vacancy rates, and downtown redevelopment efforts have focused on keeping them safe and economically viable. However, as renovations are needed, such buildings have often been difficult to reconcile with code requirements.

EXAMPLE BUILDING

2

As an example, we will consider a thirteen-story building of this type, shown in Figure 9.7. The example building’s occupancy, typical of such structures, is a bank on the first floor with offices above. The building’s height is 150 feet. It has a footprint of 50 feet wide by 200 feet deep, giving a floor area of 10,000 square feet per floor. Its corner site allows for numerous window openings on two sides, and it has a few windows on the alley side, in addition to the fire escape. The wall on the side property line is a solid brick wall. Figure 9.8 shows the first-floor plan. The structural frame is steel columns and beams. The floor slabs are reinforced concrete. At the time the building was constructed, this was called Type I construction. In today’s codes, it is Type I-A.

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Figure 9.7 In this community, this high-rise building is the only structure of this height in the historic core. Buildings like this often have safety issues that limit their rehabilitation. © Melvyn Green

Figure 9.8 A plan view of Example Building 2, an early twentieth-century high-rise building typical in cities throughout the United States. © Melvyn Green

Exterior walls are brick infill, filling the space between the steel columns and beams. The first floor has the high ceilings and large spaces that are typical of traditional bank occupancies. Alongside the bank lobby is an elevator and stair lobby that accesses the building’s upper floors. Between the first and second floors, the stair is a “grand stairway.” The treads and risers are marble, as is the wainscot. The stairway structure is steel. At each upper level above the first is a small lobby. Upper-level flights of stairs are narrower than the grand stair, but of the same construction. Wall construction in the stair shaft is hollow clay tile, finished with plaster and marble wainscot at all levels.

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Example Buildings

95

The lobby at each level connects with a corridor that accesses each of the tenant spaces of that floor. The corridor also connects to a fire escape that descends to the alley. The corridor construction is wood lath and plaster, with wood wainscot to a height of 7 feet. Corridor doors are glazed, with a transom above and a grille below for air movement. The interior of the tenant spaces consists of plaster finish on the walls and ceiling. Baseboards and trim are wood. The wall construction between the original tenants was hollow clay tile. Other partitions are wood lath and plaster, with recent alterations of plaster on metal lath or gypsum wallboard. The original building used radiators for heating, and had no mechanical air conditioning. Possible issues with this building are the open stairway and corridor construction. The adequacy of the electrical system will need to be considered. There are many retroactive requirements for high-rise buildings, including fire service elevator controls, fire alarm, both audible and visual systems, and an elevator lobby enclosure. These may vary by state and jurisdiction in various areas of the country. The following chapters discuss the requirements and approach of each of the compliance methods. Examples of a one-story commercial and multistory building undergoing various types of alterations and occupancy changes are presented. The IEBC requires that the designer follow one system or the other throughout the design. As will be seen in the examples, each code compliance approach and the extent of the construction in each case, may dictate which approach is best for the project. Each project is different, and it is important to carefully evaluate which approach is best for each project.

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CHAPTER

10

International Existing Building Code̶Prescriptive Compliance Method

The provisions of Chapter 3 of the IEBC apply to the prescriptive compliance method. This method is essentially the process contained in Chapter 34 (Existing Structures) of the IBC, discussed earlier in this book, which contains provisions for alteration, repair, additions, and change of occupancy for existing buildings. These provisions will usually apply where other codes, such as state or legacy model building codes, are used, and the process discussed in this section may be applicable to such codes.

GENERAL For nonhistoric buildings, Chapter 3 of the IEBC states that any new work, installation and alterations of finishes and systems, as well as structural changes shall conform to the requirements of the current building code. For existing elements, it provides that “portions of the structure not altered and not affected by the alteration are not required to comply with the code requirements for a new structure,” thus acknowledging the principle of nonconforming rights. This sentence is not contained in the 2009 IEBC but may be implied from the provisions. For example, this chapter provides that most existing stairways may remain, since altering an existing stairway to the current code requirements would require structural changes. The chapter goes on to state that nonstructural alterations may be made with the same materials as the existing materials. However, the extent of approved use of various archaic materials is unclear and based on the judgment of the code official. Provisions for historic buildings in IBC Chapter 34 include the statement that “the provisions of this chapter relating to the construction, repair, alteration, restoration and movement of structures and change of occupancy, shall not be mandatory for

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historic buildings where such buildings are judged by the code officials to not constitute a distinct life safety hazard.”

ADDITIONS, ALTERATIONS, AND REPAIRS This chapter of the code starts with requirements for additions, alterations, and repairs. The initial provision discusses height and area. Although a building, plus additions, may not exceed the allowable height and area limitations for its occupancy and construction type, historic buildings will usually have the right to retain their current height and area even if they exceed the current limits. Since most additions change the structural loads on a building, initial requirements for additions relate to structural loads and forces. Typically historic structures have horizontal additions; seldom are they vertical. This section has been reorganized and significantly revised in the 2009 IEBC. It is now divided into three specific sections. This has resulted in some renumbering of the remainder of the chapter. Section 302 is for additions. It clarifies some provisions and states that the existing building together with the addition are no less conforming with the provisions of this code than the existing building prior to the addition. This section also includes additional subsections for structural load-carrying elements. Section 303 is for alterations. As with previous editions of the code, all new work must conform to the IBC and no work shall make the structure any less conforming than it was before the alteration. There are also extensive structural provisions for vertical and lateral load-carrying members. Voluntary seismic improvements are permitted without meeting the IBC requirements. Additional provisions include design live loads and exit system capacity factors. Section 304 relates to repairs. As noted earlier in this text, the provisions for repair to damaged buildings are included. Extensive provisions for repairs to earthquake-damaged buildings are contained in this section. The term “substantial structural damage” will trigger an evaluation and possible upgrades. Damage to elements carrying gravity load will also require an evaluation and possible upgrade of the structural member. In the case of less than substantial structural damage, repairs are permitted to restore the building to its predamaged state using materials similar to those originally installed. Traditionally, when a building was damaged by fire, the new materials installed to replace the fire-damaged material were the same as originally used. An example of a one-story retail or industrial building comes to mind. Not clear in this section is whether the entire building must be evaluated to determine if there is substantial structural damage. Obviously, this may trigger many more repairs to a building, perhaps a full roof structure replacement and upgrade of connections to the walls.

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Additions, Alterations, and Repairs

99

There are special requirements for flood-hazard areas. Alterations and additions may be defined as a “substantial improvement” and require upgrading to flood standards. This may be significant for structures that are not designated as historic. A historic structure that will remain classified as a historic structure after the proposed work is not considered as having substantial improvement and is exempt from meeting all the flood requirements.

Structural and Seismic Requirements The prescriptive compliance method includes detailed structural and seismic requirements. For structural alterations and additions, this section is the same as in the IBC, requiring additions to comply if separated structurally from the existing building. If the existing building and the addition are attached, then the combined structure must comply, subject to several conditions. Alterations may require seismic rehabilitation of the structural element if the load increase exceeds a certain amount.

2009 International Existing Building Code 307.4 Structural. When a change of occupancy results in a structure being reclassified to a higher occupancy category, the structure shall conform to the seismic requirements for a new structure of the higher occupancy category. Where the existing seismic force-resisting system is a type that can be designated ordinary, values of R, Ω0 and Cd for the existing seismic force-resisting system shall be those specified by this code for an ordinary system unless it is demonstrated that the existing system will provide performance equivalent to that of a detailed, intermediate, or special system. Exceptions: 1. Specific seismic detailing requirements of this code and Section 1613 of the International Building Code for a new structure shall not be required to be met where it can be shown that the level of performance and seismic safety is equivalent to that of a new structure. Such analysis shall consider the regularity, over strength, redundancy, and ductility of the structure within the context of the existing and retrofit (if any) detailing provided. 2. When a change of use results in a structure being reclassified from Occupancy Category I or II to Occupancy Category III and the structure is located in a seismic map area where SDS < 0.33, compliance with the seismic requirements of this code and Section 1613 of the International Building Code are not required.

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In the 2012 IEBC, former Chapter 3 has become Chapter 4. New Section 407.4 text reverts back to 2006 IEBC text but continues to reference Section 1613 of the IBC.

2012 International Existing Building Code 407.4 Structural. When a change of occupancy results in a structure being reclassified to a higher risk category, the structure shall conform to the seismic requirements for a new structure of the higher risk category. Exceptions: 1. Specific seismic detailing requirements of Section 1613 of the International Building Code for a new structure shall not be required to be met where the seismic performance is shown to be equivalent to that of a new structure. A demonstration of equivalence shall consider the regularity, overstrength, redundancy and ductility of the structure. 2. When a change of use results in a structure being reclassified from Risk Category I or II to Risk Category III and the structure is located where the seismic coefficient, SDS, is less than 0.33, compliance with the seismic requirements of Section 1613 of the International Building Code is not required.

Structures such as a warehouse or office must support their anticipated floor loads. An exception for existing live loads permits the structure to use the loads required at the time of construction rather than current code requirements. The code requires that the live load be posted where a reduced live load is permitted. Often in rehabilitation structural members may be cut to permit installation of mechanical and electrical equipment. If any deteriorated conditions are found in trusses or in other structural members, they must be repaired.

Nonstructural Alterations and Repairs For nonstructural alterations and repairs, the chapter provides that Nonstructural alterations or repairs to an existing building or structure are permitted to be made of the same materials of which the building or structure is constructed, provided that they do not adversely affect any structural member or the fire-resistance rating of any part of the building or structure.

This provision permits retaining of historic fabric but does not provide the tools to guide the evaluation of exactly what “adversely” means. This section has changed wording that may simplify it in the 2009 IEBC.

Other Requirements Existing stairways, if repaired and replaced, are not required to meet the current code for rise and run. To do so would typically require structural alterations.

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Change of Occupancy Classification

101

Existing fire escapes are permitted to remain and continue to serve as part of the means of egress system. Each fire escape must be checked to verify its condition and structural adequacy. IEBC Chapter 3 also provides requirements for accessibility for existing buildings. Section 304 in the 2006 IEBC (306 in the 2009 IEBC) includes a requirement for glass, requiring compliance with current code provisions if glass is replaced or new glass is installed. Other provisions include energy conservation requirements and electrical, fuel gas, mechanical system, and plumbing system alterations.

CHANGE OF OCCUPANCY CLASSIFICATION Following in the traditional code approach, the change of occupancy provisions of the prescriptive compliance method state that No change shall be made in the use or occupancy of any building that would place the building in a different division or the same group of occupancy or in a different group of occupancies, unless such building is made to conform with the requirements of the International Building Code for such division or group of occupancy.

This section goes on to permit the code official latitude to approve projects that do not fully comply by stating Subject to the approval of the building (code) official, the use or occupancy of existing buildings shall be permitted to be changed and the building is allowed to be occupied for purposes in other groups without conforming to all the requirements of the International Building Code for those groups, provided the new or proposed use is less hazardous, based on life and fire risk, than the existing use.

In general, a change of occupancy will entail a review of the fire and life safety systems of the building. This may require changes to the exit system. See Figures 10.1 and 10.2.

Figure 10.1 This historic railroad station is to be converted into a city hall, offices, and community college classrooms. The exit system was a single stairway in the center of the building. Rehabilitation required adding a second stairway at the end of a long dead-end corridor. © Melvyn Green

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Figure 10.2 The addition of a new stairway on the secondary elevation of this building had the added benefit of creating a public space for events. © Melvyn Green

Many historic structures, particularly early twentieth-century high-rise buildings, use lobbies and corridors architecturally, often in ways that lessen their performance as exitways. For example, ornate wood paneling may be a feature of such structures. Adding to the problem, corridor doors may, in years previous to the use of air conditioning, have included vents and transoms to allow airflow. These problems are not insoluble, but they do require expert attention. Other archaic materials, such as wood lath and plaster, have been tested for fire performance and are considered acceptable in meeting the corridor’s fire rating requirement.

Structural Requirements Structural requirements with a change of occupancy may trigger seismic retrofit. For structural and seismic safety, the IBC provides a table, Table 1604.5— Occupancy Category of Buildings and Other Structures, that groups occupancies into categories based on life and public safety risk. When a building undergoes a change of occupancy, and the structure is reclassified to a higher occupancy category in this table, the entire structure must conform to the seismic requirements for a new building. There are exceptions, primarily in regions of lower seismicity. This occurs when the occupancy category is changed to a higher category but the structure is located in a region of low to moderate seismicity.

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Evaluating the Prescriptive Compliance Method for a Project

103

Conclusion For all existing buildings, including historic structures, there is room for judgment by the code official when a change of occupancy is proposed under the prescriptive compliance method. The degree of judgment depends to a large extent on the differences in code requirements between the existing use and the proposed use. Experienced building owners and code officials tend to be comfortable with this level of subjectivity; others may prefer either the work area compliance method or the performance compliance method. Several examples at the end of this chapter illustrate how this compliance method works. A summary chapter, Chapter 14, discusses and compares the three compliance methods.

EVALUATING THE PRESCRIPTIVE COMPLIANCE METHOD FOR A PROJECT To evaluate the effectiveness of the prescriptive compliance method for a particular project, the following considerations should be addressed: 1. Is the building designated as historic? If not, most new work must comply with the new construction provisions of the IBC. If the building is designated as historic, any needed alternatives to code compliance would be negotiated, depending on the judgment of the code official. Clearcut alternatives are not spelled out in the prescriptive compliance method. 2. Is there a change of occupancy? If so, what is the proposed occupancy group and what was the building’s historic occupancy group? The character of occupancy will determine most of the fire and life safety requirements. A change of occupancy may trigger requirements for changes to the exit system if the number of occupants increases. In addition, the new occupancy may result in an increased floor load, with required structural upgrading. In historic buildings, this may result in significant changes to historic fabric. 3. Where is the building located on the site? Fire spread between buildings has always been a primary concern of building codes. Siting also determines the required fire resistance of exterior walls and whether window and door openings are allowed. Where codes were not in effect at the time the building was constructed, or where requirements have changed, distance of windows and doors from the property line may be an issue. If a change of occupancy is proposed, previously permitted openings may not be in compliance for buildings in the new use. Minor problems in this area may be solvable, but significant discrepancies can be difficult to overcome. This is especially true for historic buildings, where

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exterior historic fabric may be stringently regulated. The acceptability of the specific conditions is at the judgment of the building official. 4. What is the type of construction, the height, and the occupiable area? Permitted types of construction vary by occupancy and building size. IBC Chapter 5 contains the new construction regulations for permitted height and area based on occupancy. In building rehabilitation, the problem is attacked from the other side— given the construction type and existing building height and area, the designer can determine which occupancies are feasible. Although it is possible to overcome some difficulties in this area by providing fire separations in a building, changing a building to an occupancy with more stringent requirements than those for which it was designed may be a challenge. More structural safety fire resistance will be required based on occupancy and building height. For example, the code may not permit assembly use above the second floor in a wood building unless it has a specified fire rating such as 1-hour fire resistant throughout. Attempting to modify such basic building characteristics as fire rating and compartmentation may cause serious damage to historic fabric, where exterior historic fabric may be stringently regulated. 5. Is the building in an area that has recently been recognized as a seismic region? If this is the case, seismic requirements may be imposed retroactively on part or all of the building, depending on the type and extent of the proposed work. Buildings undergoing a change of occupancy will be affected the most if the risk to occupants is increased. Retroactive provisions for masonry structures may be less restrictive than the code for new construction. These provisions should be considered under the alternate materials and methods option contained in all building codes, where exterior historic fabric may be stringently regulated. The IEBC Appendix Chapter A1 has provisions for seismic rehabilitation of unreinforced masonry bearing wall buildings. This may have to be the basis for an appeal as the prescriptive method does not specifically refer to the Appendix. 6. How can deficiencies be resolved? One source of solutions for deficiencies may be the other chapters of the International Existing Building Code. Use of the hazard ranking tables, and supporting text, will provide information about perceived risk and the goals of the code developers. Another approach would be to do a trial analysis of conditions, using the IEBC performance compliance method. Even if such an analysis were performed for information only, it would offer insight into the building’s deficiencies and how they might be corrected. Helpful information might also be found in older codes, such as the Uniform Code for Building Conservation (UCBC) as well as local code experience. Sometimes in communities that have had a disaster, there may be some experience or policy to guide the resolution of problems relating to life and fire risk, where exterior historic fabric may be stringently regulated.

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Prescriptive Compliance Method—Examples

105

PRESCRIPTIVE COMPLIANCE METHOD̶EXAMPLES Two different building types are to be considered as examples of the IEBC compliance methods: a low-rise “Main Street” retail, office, or small restaurant structure and a high-rise multistory office building. These are the buildings that were described as examples in Chapter 9. The existing low-rise mercantile building is to be evaluated in three examples: 1. A simple project in a retail store (or mercantile occupancy), a tenant improvement including new lighting, ceiling, floor covering, and paint. This project involves no change of occupancy character or group. 2. Changing from a mercantile to office use. This is a change of occupancy group, from mercantile to office, an M to B occupancy classification. 3. A change from mercantile to assembly by changing the space to a small dining facility. This is a change from an M to an A-2 occupancy. The high-rise, 13-story office building also has three examples. It is to be evaluated for 1. A tenant improvement project involving new lighting, floor covering, and ceiling with no reconfiguration of space. All work is within the tenant space. 2. A larger tenant alteration that may involve the addition of a door into a corridor as well as some minor reconfiguration of the interior space. 3. The rehabilitation of an entire floor. Each of the alteration projects described earlier is evaluated in detail following the prescriptive method. For simplicity, features other than those discussed are assumed to be acceptable. Refer to Figure 9.3 for the low-rise building and to Figure 9.8 for the high-rise building plans. The examples illustrate a few unanswered questions, since the prescriptive approach requires judgment by the code official. Such questions may trigger the application of other code requirements and increase the scope of the planned project. Before starting a design project, it is best to consider the following questions:

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“What is the best method to use to achieve code compliance for this project?”



“By choosing one method over another, will work interruptions during construction be more or less likely?”



“Does the easiest method during plan preparation make for a quick approval for the necessary permits?”



“How does the method of compliance affect the end product?”



“Which compliance method would best serve the short- and long-term goals of the client/building owner?”

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EXAMPLE BUILDING

1

Low-rise “Main Street” Building SCOPE: Low-rise, M to M occupancy (retail furniture store to retail clothing shop)

Prescriptive—This approach requires that all newly installed work comply with the requirements of the IBC for alterations, including materials and systems, such as the electrical lighting. No reduction in the existing level of compliance (i.e., safety) is permitted. Refer to Figure 9.3 for the building plan. The code states that portions of the structure not altered and not affected by the alteration are not required to comply with the code requirements for a new structure. Requirements for energy conservation would not have an effect on this structure. Any new electrical work must comply but there is no requirement that the entire system must be upgraded to current standards. Accessibility improvements may be required, such as an accessible entrance with appropriate signage. Historic buildings may consider alternative solutions when the impact on the structure would result in a significant loss of historic fabric or character.

EXAMPLE BUILDING

1

SCOPE: Low-rise, M to B occupancy (retail furniture store to single-tenant office)

Prescriptive—Buildings undergoing a change of occupancy group are technically required to comply fully with the IBC for new buildings. There is an exception in the code permitting a change of use or occupancy without full compliance with the IBC. This provision is the same as in the IBC, and permits the building official to allow a change of occupancy if the proposed use is less hazardous, based on fire and life risk, than the existing use. The new work must comply with the IBC. However, practical considerations may demonstrate that the change of occupancy does not increase the fire or life risk. Examples of this might be to demonstrate that the occupant load has not increased. Another example might be that the business occupancy has less combustible content. Also, the users of the office occupancy are more likely to be familiar with the building and its exits. If the building is a designated historic structure, the change of occupancy will not cause full compliance to be required if the code official determines that the building does not constitute a distinct life safety hazard. Note that for nonhistoric buildings, it must be demonstrated that the proposed use is less hazardous, based on fire and life risk, than the existing use; but for the historic structure, it must only be shown that the new use does not constitute a distinct life safety hazard. Regardless, it is a subjective determination that may affect the construction requirements.

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Prescriptive Compliance Method—Examples

Prescriptive—This change is to an assembly use, indicating an increase in the number of occupants in the building. As in the previous example, buildings undergoing a change of occupancy group are required to comply with the IBC for new buildings. The code exception described in the previous example permits use or occupancy to be changed without full compliance with the IBC if the new use is less hazardous, based on fire and life risk, than the existing.

EXAMPLE BUILDING

107

1

SCOPE: Low-rise, M to A-2 occupancy (retail furniture store to small restaurant, 10 max. height value allowed (Equation 13-1, 2006 IEBC) (w/ values from Table 503, 2006 IBC)

2009 IEBC Height value, feet =

( AH) − (EBH) × CF 12.5

Height value, feet =

55 ft − 15 ft × 3.5 12.5

Height value, feet = 11

(Equation 13-1, 2009 IEBC)

Height value, stories = ( AS − EBS) × CF Height value, stories = (2 stories − 1 story) × 3.5 Height value, stories = 3.5 ≈ 4.0 (Equation 13-2, 2009 IEBC) (w/ values from Table 503, 2009 IBC)

© International Code Council

6.2 Building area – The building area score is a function of the allowable and actual area per floor for a specific occupancy classification. This is then compared to

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that permitted by the International Building Code. It is a somewhat more complex calculation than that for the height value. Equation 13.3 in the 2009 IEBC is used to determine the allowable area per story, Aa, for this example building. The allowable area per story for a building of this type and occupancy is determined by Section 506.1 and Table 503 of the IBC, seen in Figure 13.2. The IBC permits increases in allowable area based on frontage on a public way. Increases are also allowed for automatic sprinklers. Example Building 1 does not qualify for frontage or sprinkler increases, so the frontage and sprinkler increase factors (If and Is, respectively) are both 0. Looking at the solved equation, the allowable area per story expressed here is seen: A a = (1+ If + Is )× A t A a = (1+ 0 + 0 )×12, 500 sf A a = 12, 500 sf (Equation 13-3, 2009 IEBC)

© International Code Council

In the 2006 edition of the IEBC, three equations were used to determine the allowable area per story for a building. In addition to the allowable area (Aa), a limit was set for the allowable area (Aa,max), which necessitated finding a value Amax. Notice that the equation numbering was slightly different in the 2006 IEBC than it is in the 2009 IEBC. Those equations are shown solved for this example for comparative purposes here: Aa =

(100 + If + Is )× A t 100

Aa =

(100 + 0 + 0 )×12, 500 100

Aa = 12,500 sf ← governs Amax = 3 × Aa as calculated in accordance with Section 506.1 off the International Building Code. A max = 3 × 8500 sf = 25, 500 sf (Equation 13-2, 2006 IEBC) A a,max =

A max Number of stories

A a,max =

37, 500 sf = 37, 500 sf 1 (Equation 13-3, 2006 IEBC)

© International Code Council

Using the 2009 IEBC equation, the simplification to a single equation to find allowable area per story yields exactly the same value that is found using the multiple equations in the 2006 edition. In either the 2006 or 2009 editions of the IEBC, the

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critical allowable area per story is entered into Equation 13.4 and solved for the area value that is to be used in the Table 1301.7 summary sheet. Area valuei =

Area value =

Actual areaa ⎞⎟⎤⎥ Allowable areai ⎡⎢ ⎛⎜ Actual area i ⎟⎟ 1− ⎜ +... + Allowable areaa ⎟⎠⎥⎥⎦ 1200 square feet ⎢⎢⎣ ⎜⎜⎝ Allowable areai 12500 sf ⎡⎢ ⎛⎜ 2500 sf ⎞⎟⎤⎥ ⎟⎟ 1− ⎜ 1200 ⎢⎢⎣ ⎜⎜⎝ 12500 sf ⎟⎠⎥⎥⎦

Area value = 8.3 ≈ 8 (Equation 13-4)

© International Code Council

Rounding this number to the nearest integer, the area value is computed to be 8. The maximum permitted positive area value is 50 percent of the mandatory safety scores for fire safety (MFS) for the proposed occupancy per Table 1301.8 of the IEBC. A copy of this table is found at the end of this example in Figure 13.16. This gives an area value of 0.5 × (23) = +11.5 for an M occupancy category. The computed area value is less than this maximum, so the score of +8 is entered on the Table 1301.7 summary sheet, seen in Figure 13.15 at the end of this example. Note the use of positive numbers. As shown below, negative numbers will be obtained for some aspects of the building. It is important to keep track of numerical sign throughout the tabulations. 6.3 Compartmentation—Compartments in a building limit the spread of fire by enclosing areas with walls as well as the floors and ceiling assemblies. The smaller the compartment, the higher the score will be. This building has only the one floor, with nonrated partitions that would do little to limit the spread of fire and fail to meet the required 2-hour fire-resistance rating for compartment wall construction. The compartment size is therefore the single floor of 2500 square feet. Looking at Table 1301.6.3, seen here in Figure 13.4, we see that for an M occupancy, the compartment size of 2500 square feet or less is a Category e with a score of +22.

Figure 13.4 Table 1301.6.3 of the 2009 IEBC provides a quantitative value to express the net area created by fire barriers. Where the building is not divided into more than one compartment, the compartment size is taken as the total floor area on all floors. © International Code Council

TABLE 1301.6.3 COMPARTMENTATION VALUES CATEGORIES

OCCUPANCY

a Compartment size equal to or greater than 15,000 square feet

b Compartment size of 10,000 square feet

c Compartment size of 7,500 square feet

d Compartment size of 5,000 square feet

e Compartment size of 2,500 square feet or less

A-l. A-3

0

6

10

14

18

A-l

0

4

10

14

18

A-4, B, E, S-2

0

5

10

15

20

F, M, R, S-l

0

4

10

16

22

For SI: 1 square foot = 0.0929 m2.

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TABLE 1301.6.4 SEPARATION VALUES

TABLE 1301.6.5 CORRIDOR WALL VALUES

CATEGORIES

CATEGORIES

OCCUPANCY

a

b

c

d

e

OCCUPANCY

a

b

ca

da

A-l

0

0

0

0

1

A-l

10

4

0

2

A-2

5

3

0

1

3

A-2

30

12

0

2

R

4

2

0

2

4

A-3, F, M, R, S-l

7

3

0

2

A-3, A-4, B, E, F, M, S-1

4

3

0

2

4

A-4, B, E, S-2

5

2

0

5

S-2

5

2

0

2

4

Figure 13.5 Table 1301.6.4 of the 2009 IEBC is used to determine the rating of the fire separation between tenants in the building being evaluated. Category c is to be used when there is only one tenant within the fire area. © International Code Council

a. Corridors not providing at least one-half the travel distance for all occupants on a floor shall use Category b.

Figure 13.6 Table 1301.6.5, 2009 IEBC, provides the fire rating of corridor wall value to be entered into the summary sheet of Table 1301.7. Buildings without corridors, as permitted by Section 1014 of the IBC, may use Category c values. © International Code Council

This is the highest score for an M occupancy; additional compartmentation would not affect the score. 6.4 Tenant and dwelling unit separations—Separation, like compartmentation, limits the spread of fire between spaces occupied by different tenants within the same building. Where there is only one tenant, the tenant separation category is c. Table 1301.6.4, seen in Figure 13.5, gives this category a score of zero. Note that changes to the category definitions in the 2009 IEBC to referenced IBC sections may affect a project, depending on occupancy or fire assembly construction. When using a new code, it is always best to follow each reference back to ensure that all of the conditions are applicable. In this example with one tenant, these subtle changes have no effect. 6.5 Corridor walls—Corridor walls need to be evaluated to determine whether they permit the spread of fire into the corridor. This is of special concern since building occupants are forced into a specific path and confined space. In this case, there are no required fire-rated corridor walls for egress; therefore, this building was determined to have a Category c condition with no corridors, as permitted by Section 1014 of the 2009 IBC. The score for this condition and occupancy is zero in Table 1301.6.5, seen in Figure 13.6. 6.6 Vertical openings—The structure is a one-story building, so Section 1301.6.6 of the IEBC states that a value of +2 is to be entered on the Table 1301.7 summary sheet. 6.7 HVAC system—Ductwork for heating and cooling systems will also move smoke through the building. Any heating system that serves only one story, i.e., a one-story building, is classified as Category e. The score is a +5. 6.8 Automatic fire detection—Smoke detectors will notify occupants of a fire, permitting a faster exit than waiting for other notifications. In this building, there were

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TABLE 1301.6.8 AUTOMATIC FIRE DETECTION VALUES

167

TABLE 1301.6.9 FIRE ALARM SYSTEM VALUES

CATEGORIES

CATEGORIES

OCCUPANCY

a

b

c

d

e

OCCUPANCY

a

ba

c

d

A-l, A-3, F, M, R, S-l

10

5

0

2

6

A-l, A-2, A-3, A-4, B, E, R

10

5

0

5

A-2

25

5

0

5

9

F, M, S

0

5

10

15

4

2

0

4

8

A-4, B, E, S-2

Figure 13.7 Table 1301.6.8 of the 2009 IEBC provides a value that describes the smoke-detection capability based on the location and operation of automatic fire detectors in accordance with Section 907 of the IBC. © International Code Council

a. For buildings equipped throughout with an automatic sprinkler system, add 2 points for activation by a sprinkler water-flow device.

Figure 13.8 Table 1301.6.9 of the 2009 IEBC is used to quantify how well the fire alarm system meets Section 907 of the IBC. © International Code Council

no smoke detectors, placing it in Category a—none. Table 1301.6.8, seen in Figure 13.7, shows the score is a –10 for this M occupancy. 6.9 Fire alarm systems—This building has no fire alarm system, which is Category a—none. The score of zero is tabulated in Table 1301.6.9, seen in Figure 13.8, for this M occupancy. 6.10 Smoke control—The control of smoke is a principal safety element. This structure receives a Category a—none. A score of zero is assigned in Table 1301.6.10, seen in Figure 13.9, to the last two columns in the Table 1301.7 summary.

TABLE 1301.6.10 SMOKE CONTROL VALUES CATEGORIES OCCUPANCY

a

b

c

d

e

f

A-1, A-2, A-3

0

1

2

3

6

6

A-4, E

0

0

0

1

3

5

B, M, R

0

2

a

a

a

a

4a

F, S

0

2a

3a

3a

3

2a

3

3a

3

a. This value shall be 0 if compliance with Category d or c in Section 1201.6.8 1 has not been obtained.

Figure 13.9 Smoke control values are given here in Table 1301.6.10

of the 2009 IEBC. © International Code Council 6.11 Means-of-egress capacity and number—The means-of-egress capacity and number need to be evaluated. In this building, there is one main door in the storefront and one door at the rear, providing two means of egress. Traditionally, Chapter 10 of the IBC has been used to calculate the required egress width (capacity) for the number of occupants. In the 2009 IEBC, Table 1301.6.11(1) has been included to clarify exactly how that required width is to be calculated. Using this table (which is similar to, but not exactly, that found in the 2006 IBC), the number of occupants for the proposed M occupancy (2500 sq ft/30 sq ft per person = eighty-three persons), multiplied by the factor 0.2 found in Table 1301.6.11(1) for an unsprinklered building, yields a required egress width of 17 inches. The minimum size of exits given in the IBC is greater than the calculated 17 inches; nonetheless, 17 inches is the required capacity that is used to determine how well the capacity is met or exceeded. The number of exits and corridor width (capacity) meets current code and is complying. This parameter is rated Category c, capacity of the means of egress is equal to or exceeds 125 percent of the required means-of-egress capacity (the 17 inches that was just calculated multiplied by 1.25), and is in compliance for the minimum required width dimensions (the typical 32-inch clear opening required by the IBC for an accessible egress). Using Table 1301.6.11(2), seen in Figure 13.10, a score of +1 is found and entered in the last two columns of the summary sheet, seen in Figure 13.15.

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TABLE 1301.6.11(1) EGRESS WIDTH PER OCCUPANT SERVED WITH SPRINKLER SYSTEMa

WITHOUT SPRINKLER SYSTEM Stairways (Inches per occupancy)

Other egress components (Inches per occupancy)

Stairways (Inches per occupancy)

Other egress components (Inches per occupancy)

0.3

0.2

0.2

0.15

Hazardous: H-1, H-2, H-3, H-4

Not permitted

Not permitted

0.3

0.2

Institutional: I-2

Not permitted

Not permitted

0.3

0.2

OCCUPANCY Occupancies other than those listed below

For SI: 1 inch = 25.4 mm. a. Buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.1.1 or 903.3.1.2.

TABLE 1301.6.11(2) MEANS OF EGRESS VALUES CATEGORIES a

OCCUPANCY

a

b

A-1, A-2, A-3, A-4, E

10

0

M

3

0

c

d

e

2

8

10

1

2

4

B, F, S

1

0

0

0

0

R

3

0

0

0

0

a. The values indicated are for buildings six stories or less in height. For buildings over six stories above grade plan, add an additional -10 points.

Figure 13.10 Tables 1301.6.11(1) and 1301.6.11(2) of the 2009 IEBC shown here provide the necessary information to determine a value that describes means-of-egress capacity and the number of exits available to the building occupants. © International Code Council

TABLE 1301.6.12 DEAD-END VALUES CATEGORIESa OCCUPANCY

a

b

c

A-1, A-3, A-4, B, F, M, R, S

2

0

2

A-2, E

2

0

2

a. For dead-end distances between categories, the dead-end value shall be obtained by linear interpolation.

Figure 13.11 Table 1301.6.12 of the 2009 IEBC provides values for dead-end conditions in spaces that are required to be served by more than one means of egress. © International Code Council

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6.12 Dead ends—Corridor dead ends can trap occupants in an emergency. Since the exit path has no dead ends, this building was deemed to be a Category c—no dead ends. The score in this example is +2, found in Table 1301.6.12, seen in Figure 13.11, for this occupancy. It is entered into the last two columns of the summary sheet. 6.13 Maximum exit access travel distance—Building codes today allow different travel distances to exits, depending on whether the building is fire sprinklered or not. Travel distance in this building is the distance from the farthest corner of the building to the front or rear exit. This building has an exit distance of about 60 feet. The allowable exit access travel distance for an M occupancy without a sprinkler system is

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200 feet. The value for maximum exit access travel is given in Equation 13.6 as a function of these two values. The resulting value of +14 seen here is entered into the summary sheet.

Points = 20 ×

Maximum allowable travel distance − Maximum actual travel distance Maximum allowable travel distance

0× Points = 20

200 ft − 60 ft 200 ft

Points = 14 (Equation 13-6)

© International Code Council

6.14 Elevator controls—This one-story building does not have an elevator. A score of zero shall be entered in all three columns of the summary sheet for a single-story building. 6.15 Means-of-egress emergency lighting—An illuminated exit path is critical. When this building was constructed, this was not required. For this example, it is assumed not present. Category a indicates means-of-egress lighting and exit signs not provided with emergency power. Where two exits or more are required, a value of NP (not permitted) is given in Table 1301.6.15, seen here in Figure 13.12. A system meeting the minimum standards will have to be provided, regardless of the total building score. A score of NP is entered on the example summary sheet for this category. 6.16 Mixed occupancy—This building has only one occupancy group, M. Since this building is without mixed occupancies, the value is zero. 6.17 Automatic sprinklers—This building does not have an automatic sprinkler system, nor are sprinklers required. It is classified as Category c—sprinklers are not required; none are provided. Figure 13.13 shows Table 1301.6.17, which is used to find the value used to evaluate this safety element. The score for an M occupancy is

TABLE 1301.6.15 MEANS-OF-EGRESS EMERGENCY LIGHTING VALUES NUMBER OF EXITS REQUIRED BY SECTIONS 1018.1 AND 1018.2 OF THE INTERNATIONAL BUILDING CODE

a

b

c

Two or more exits

NP

0

4

0

1

I

Minimum of one exit

CATEGORIES

NP = Not permitted.

Figure 13.12 Table 1301.6.15 of the 2009 IEBC provides values that express the presence and reliability of means-of-egress emergency lighting. © International Code Council

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TABLE 1301.6.17 SPRINKLER SYSTEM VALUES CATEGORIES a

OCCUPANCY

a

b

a

c

d

e

f

A-1, A-3, F, M, R, S-1

6

3

0

2

4

6

A-2

4

2

0

1

2

4

A-4, B, E, S-2

12

6

0

3

6

12

a. These options cannot be taken if Category a in Section 1301.6.18 is used.

Figure 13.13 Fire-sprinkler values given in Table 1301.6.17 of the 2009 IEBC are used to express the ability to suppress a fire based on the installation of an automatic sprinkler system. © International Code Council

TABLE 1301.6.18 STANDPIPE SYSTEM VALUES CATEGORIES OCCUPANCY A-1, A-3, F, M, R, S-1

aa 6

b

c

d

0

4

6

A-2

4

0

2

4

A-4, B, E, S-2

12

0

6

12

a. This option cannot be taken if Category a or Category b in Section 1301.6.17 is used.

Figure 13.14 Table 1301.6.18 of the 2009 IEBC gives a quantitative value to the ability to initiate an attack on a fire by making the supply of water readily available through the installation of standpipes. © International Code Council

zero in the first and third columns of the summary sheet. In the second column, the score is divided by 2, but remains zero. 6.18 Standpipes—This is a one-story building with no standpipes, nor are they required. The building is classed as Category b, and a score of zero is given for this M occupancy in Table 1301.6.18, seen in Figure 13.14. 6.19 Incidental use—Incidental uses are clearly defined in Table 508.2 of the IBC, with the required degree of fire-rated protection listed. In this building, there are no incidental uses, so the score for incidental use is given as zero. At this time, all the individual values for the existing building determined above are entered into the Table 1301.7 summary sheet in Figure 13.15. The value is the same in each column: fire safety, means of egress, and general safety, unless noted otherwise. The sum of the values in each column is determined. In this case,

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Fire safety

31

Means of egress

48

General safety

48

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TABLE 1301.7 SUMMARY SHEET - BUILDING CODE Existing occupancy

M (Retail)

Proposed occupancy

Year building was constructed

1918

Number of stories

Type of construction

III-B

Area per Floor

Percentage of open perimeter increase

0

%

Completely suppressed:

Yes

No

X

Compartmentation:

Yes

No

X

Height in feet

N/R

Required door closers:

Yes

, serving number of floors

Automatic fire detection:

Yes

No

X

Type of location

Fire alarm system:

Yes

No

X

Type

Smoke control:

Yes

No

X

Type

Adequate exit routes:

Yes

No

Dead ends:

Maximum exit access travel distance

60’

Means-of-egress emergency lighting: Yes

No

15

No

X

N/A

HVAC

X

1

2,500 sq. ft.

Corridor wall rating

Fire-resistance rating of vertical opening enclosures Type of HVAC system

M (Retail)

X

1

Yes

No

X (None)

Elevator controls:

Yes

No

N/A

Mixed occupancies:

Yes

No

X

FIRE SAFETY (FS)

MEANS OF EGRESS (ME)

GENERAL SAFETY (GS)

1301.6.1 Building Height

4

4

4

1301.6.2 Building Area

8

8

8

≤ 2500 sf, e)

22

22

22

c)

0

0

0 0

SAFETY PARAMETERS

1301.6.3 Compartmentation 1301.6.4 Tenant and Dwelling Unit Separations 1301.6.5 Corridor Walls

c)

0

0

1-story

2

2

2

1-story, e)

5

5

5

1301.6.8 Automatic Fire Detection

a)

10

10

10

1301.6.9 Fire Alarm System

a)

0

0

0

1301.6.10 Smoke Control

a)

****

0

0

1301.6.11 Means of Egress

c)

****

1

1

1301.6.12 Dead Ends

c)

****

2

2

****

14

14

1301.6.6 Vertical Openings 1301.6.7 HVAC Systems

1301.6.13 Maximum Exit Access Travel Distance 1301.6.14 Elevator Control 1301.6.15 Means of Egress Emergency Lighting 1301.6.16 Mixed Occupancies

1-story

****

0

0

a)

0

NP

NP

N/A - none

0

0

0

1301.6.17 Automatic Sprinklers

c)

0

0

0

1301.6.18 Standpipes

b)

0

****

0

N/A

0

2  0

0

31

48

48

1301.6.19 Incidental Accessory Occupancy Building score - total value * * * * No applicable value to be inserted.

Figure 13.15 The completed Table 1301.7 summary sheet for the Building 1 example, for the existing M occupancy (a retail furniture store) to be converted to a proposed M occupancy (a retail clothing store). The NP (not permitted) rating for the means-of-egress emergency lighting parameter requires work be done to improve this condition, no matter what the final scores are. © International Code Council

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Figure 13.16 Table 1301.8 of the 2009 IEBC provides mandatory scores that the building must meet or exceed in the performance compliance method. © International Code Council

 Figure 13.17 Table 1301.9 of the 2009 IEBC provides a form for finding the difference between the total building scores, found at the bottom of the summary sheet in Figure 13.15, and the mandatory building scores, from Figure 13.16. Final scores of zero or greater indicate a passing score using the performance compliance method. Any values of NP (not permitted) that were scored on the Table 1301.7 summary sheet must be corrected regardless of the final passing scores seen here. © International Code Council

TABLE 1301.8 MANDATORY SAFETY SCORESa OCCUPANCY

FIRE SAFETY (MFS)

MEANS OF EGRESS (MME)

GENERAL SAFETY (MGS)

A-1

20

31

33

A-2

21

32

32

A-3

22

33

33

A-4, E

29

40

40

B

30

40

40

F

24

34

34

M

23

40

40

R

21

38

38

S-1

19

29

29

S-2

29

39

39

a. MFS = Mandatory Fire Safety MME = Mandatary Means of Egress MGS = Mandatory General Safety

The mandatory safety score for various occupancy classifications is shown in Figure 13.16. The mandatory safety score for a Group M occupancy is subtracted from the building score. Where the final score is zero or more, the building is in compliance. Where the final score is less than zero, the building is not in compliance. The scores for this building are Fire safety

31

 (23)  8

Means of egress

48

 (40)  8

General safety

48

 (40)  8

The building scores and mandatory scores for the three groups of safety parameters can be entered into the evaluation formulas of Table 1301.9, seen in Figure 13.17. The three resulting final scores then describe the level of compliance, with positive final scores showing that the building passes the evaluation for compliance.

TABLE 1301.9 EVALUATION FORMULAS FORMULA

SCORE

PASS

FS - MFS > 0

31

(FS)



23

(MFS)



8



ME - MME ≥ 0

48

(FS)



40

(MFS)



8



GS - MGS ≥ 0

48

(FS)



40

(MFS)



8



a. FS = Fire Safety

T1201.7

T1201.9

MFS = Mandatory Fire Safety

ME = Measure of Egress

MME = Mandatory Means of Egress

GS = General Safety

MGS = Mandatory General Safety

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In this example, it is seen that all three groups of the safety parameters comply, with the exception of the required addition of emergency power to egress lighting and exit signs. If the occupancy classification is changed, an analysis must be conducted for the new occupancy group. If the building is of mixed occupancy, then each occupancy must be separately evaluated based on its area, considering separations between occupancies. In the next two examples, the same building will be evaluated for two different proposed uses. Through these examples, it can be seen how a change of occupancy classification can affect a building’s compliance using this method.

This example shows the effect of occupancy change on the building described in the previous example. The building remains the same 25-feet-wide by 100-feet-deep brick building that was described before. The construction remains Type III-B as described in today’s codes. Figure 9-3 is still an applicable plan view of the building. Only the occupancy changes in this example.

EXAMPLE BUILDING

1

SCOPE: Low-rise, Occupancy Change, M to B

Now the retail furniture store is to be replaced with a real estate office. This is a change of occupancy classification, from M to B. As a new Table 1301.7 summary sheet evaluation is filled out for this example, it can be seen how this occupancy change affects some of the previous example’s scores. The completed summary sheet is shown at the end of this example as Figure 13.18. Building height and area are once again the first items considered. In this case, since the building is Type III-B, use Table 503 of the IBC to determine the permitted height (55 feet), the permitted number of stories (four stories in the 2006 IBC and three stories in the 2009 IBC), and the permitted area (19,000 square feet) for the proposed B occupancy. Now the numerical scores are computed for the existing Type III-B building with the proposed B occupancy.

6.1 Building height—Looking at Table 503 of the 2006 IBC, previously seen in Figure 13.2, it is seen that the allowable height, in feet and in number ( AH) − (EBH) × CF of stories, remains the same for a B occupancy as it was for an Height value, feet = 12.5 M occupancy. So the calculated height value would remain the 55 ft − 15 ft same if the 2006 IBC were used. Height value, feet = × 3.5 12.5

However, in the case of the 2009 IBC, the allowable height in stories for the proposed B occupancy (3) is increased from the existing M occupancy (2). This change in the allowable heights in the IBC changes the height value that is calculated for the proposed occupancy, depending on which code edition is used. Using the 2009 IBC allowable height for this example, Equations 13.1 and 13.2 are solved. Just as before, the height value based on the number of stories is the lower value, so it is the one that is most critical. This

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Height value, feet = 11 (Equation 13-1) Height value, stories = ( AS − EBS) × CF Height value, stories = (3 3 stories − 1 story) × 3.5 Height value, stories = 7.0 (Equation 13-2, 2009 IEBC)

© International Code Council

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value is still less than the maximum score for any building height, so the score of +7 is used on the Table 1301.7 summary sheet at the end of this example. 6.2 Building area—The building area score is a function of the allowable and actual area per floor for a specific occupancy classification. Looking at Table 503 of the IBC, seen earlier in Figure 13.2, it is seen that the change in occupancy affects the number for At, which is listed as 19,000 square feet for a B occupancy. Plugging in 19,000 square feet for At into Equation 13.3 of the 2009 IEBC for this B occupancy gives the allowable area per story. Aa  (1  If  Is)  At (Equation 13-3, 2009 IEBC) Aa  (1  0  0) x 19,000 sf  19,000 sf

© International Code Council

If the 2006 IEBC, with 2006 IBC allowable values, is used, the equations look like this: Aa =

(100 + If + Is ) × At 100

Aa =

(100 + 0 + 0 ) × 19, 000 sf = 19, 000 sf ← governs 100

A max = 3 × Aa as calculated in accordance with Section 506.1 of the International Building Code. Amax = 3 × 19,000 sf = 57,000 sf (Equation 13-2, 2006 IEBC) A a, max =

Amax Number of stories

A a, max =

37, 500 sf = 37, 500 sf 1 (Equation 13-3, 2006 IEBC)

© International Code Council

Both the 2006 and 2009 code editions yield the same area value using Equation 13.4 of the IEBC: Area valuei =

Allowable areai ⎡⎢ ⎛⎜ Actual areai Actual area a ⎞⎟⎤⎥ ⎟⎟ 1 − ⎜⎜ +...+ ⎢ ⎜ 1200 square feet ⎢⎣ ⎝ Allowable area i Allowable area a ⎟⎠⎥⎥⎦

Area value =

19, 000 sf ⎡⎢ ⎛⎜ 2500 sf ⎞⎟⎥⎤ ⎟⎟ 1− ⎜ 1200 ⎢⎢⎣ ⎜⎜⎝ 19, 000 sf ⎟⎠⎥⎥⎦

Area value = 13.75 ≈ 14

© International Code Council

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Rounding the score to the nearest integer, the area value is computed to be 14. However, before the score is entered into the summary sheet, the maximum permitted value limit must be checked. The maximum permitted positive area value is 50 percent of the mandatory safety scores for the proposed occupancy per Table 1301.8, previously seen in Figure 13.16. This gives an area value of 0.5 × (30) = +15 for a B occupancy category. The computed area value is less than this maximum, so a score of +14 is entered on the Table 1301.7 summary sheet. 6.3 Compartmentation—The compartment size is still the single floor of 2500 square feet. For a B occupancy, however, the Category e compartment size of 2500 square feet or less has a score of only +2, given in Table 1301.6.3. The +2 score is entered in the summary sheet. 6.4 Tenant and dwelling unit separations—Where there is only one tenant, the tenant separation category is c. For this B occupancy, the score is the same as the previous example; it has a score of zero. 6.5 Corridor walls—For this B occupancy, a Category c condition with no corridors can still be used, as permitted by Section 1014 of the IBC. The score for this condition happens to be the same as before, found in Table 1301.6.5. Enter zero in all three columns on the summary sheet. 6.6 Vertical openings—A change in occupancy makes no difference here. The value of +2 remains the same for this one-story building. 6.7 HVAC system—This score is not affected by a change in occupancy. Continue to use Category e for this one-story building. The score is a +5. 6.8 Automatic fire detection—Here a marked difference can be seen in the score due to the change in occupancy. Table 1301.6.8, seen in Figure 13.7, states that this B occupancy only requires a score of -4 for this building with no smoke detectors, still classified as a Category a. The score of -4 is entered in the summary sheet. 6.9 Fire alarm systems—This building has no fire alarm system. This is still a Category a building, but in a B occupancy Table 1301.6.9 gives the score of -10. 6.10 Smoke control—Still no smoke control, still a Category a, none. For this category, a score of zero is also assigned to this B occupancy. Enter the zero score in the last two columns in the Table 1301.7 summary sheet at the end of this example. 6.11 Means-of-egress capacity and number—The egress capacity and number of exits has not changed, but in a B occupancy Table 1301.6.11 shows the score is a bit lower. Rate this item as a Category c; capacity of the means of egress is equal to or exceeds 125 percent of the required means-of-egress capacity, and is in compliance for the minimum number of exits and the minimum required width dimensions. Now the score is only a zero, shown in the last two columns of the summary sheet. 6.12 Dead ends—No change in score due to the change in occupancy. As before in the previous example, score this building as a Category c—no dead ends, and enter the +2 into the last two columns of the summary sheet.

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6.13 Maximum exit access travel distance—The same exit distance of about 60 feet can be taken, and the maximum allowable travel distance (200 feet) has not changed due to a B occupancy. The equation still looks the same as it did in Equation 13.6 in the previous example, and the same score of +14 is used as in the previous example. 6.14 Elevator controls—This one-story building still does not have an elevator. A score of zero is not dependent on occupancy, and shall be entered in all three columns of the summary sheet. 6.15 Means-of-egress emergency lighting—Once again it is assumed that a Category a condition exists, with means-of-egress lighting and exit signs not provided with emergency power. In this example, the B occupancy has a lower expectation of the combustibles and/or number of people filling this space. If the entire 2500 square feet were divided by the occupant load factor of 100 square feet per person (found in Table 1004.1.1 of the IBC), only twenty-five people would be calculated for this space. For fewer than thirty persons, Table 1015.1 of the IBC states that only a single exit is required. So for this B occupancy, Table 1301.6.15 gives a value of zero to enter on the summary sheet. Additionally, a system meeting the minimum standards for emergency power for means-of-egress lighting and exit signs will not have to be provided. 6.16 Mixed occupancy—This building has only one occupancy group, this time a B occupancy. As a building without mixed occupancies, the value is zero. 6.17 Automatic sprinklers—This building does not have an automatic sprinkler system, nor are sprinklers required. This B occupancy is classed as Category c—sprinklers are not required; none are provided. If this tenant space had a different category describing its equipment, there might be a change in score due to the change in occupancy. However, for this proposed office, with Category c conditions, the score for a B occupancy is still zero. Enter the score in the first and third columns of the summary sheet. In the second column, the score is divided by 2, but remains zero. 6.18 Standpipes—This remains a one-story building, with no standpipes, nor are they required. Nothing has changed in this score due to the change in occupancy. The building is classed as Category b, and Table 1301.6.18 gives a score of zero. 6.19 Incidental use—In this building, there are again no incidental uses, so the score for incidental uses is still given as zero. At this time, all the individual values that have been tabulated for the existing building with a proposed change to a B occupancy are seen in the Table 1301.7 summary sheet in Figure 13.18. The value is the same in each column: fire safety, means of egress, and general safety, unless noted otherwise. The sum of the values in each column is determined. In this case,

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Fire safety

34

Means of egress

50

General safety

50

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TABLE 1301.7 SUMMARY SHEET - BUILDING CODE Existing occupancy

M (Retail)

Proposed occupancy

Year building was constructed

1918

Number of stories

Type of construction

III-B

Area per Floor

Percentage of open perimeter increase

0

%

Completely suppressed:

Yes

No

X

Compartmentation:

Yes

No

X

Height in feet

N/A

Required door closers:

Yes

, serving number of floors

Automatic fire detection:

Yes

No

X

Type of location

Fire alarm system:

Yes

No

X

Type

Smoke control:

Yes

No

X

Type

Adequate exit routes:

Yes

No

Dead ends:

Maximum exit access travel distance

60’

Means-of-egress emergency lighting: Yes

No

X

1301.6.1 Building Height

1301.6.5 Corridor Walls 1301.6.6 Vertical Openings 1301.6.7 HVAC Systems

X

1

Yes

No

X (None)

Elevator controls:

Yes

No

N/A

Yes

No

X

MEANS OF EGRESS (ME)

GENERAL SAFETY (GS)

7

7

7

14

14

14

≤ 2500 sf, e)

20

20

20

c)

0

0

0 0

1301.6.2 Building Area 1301.6.3 Compartmentation

No

Mixed occupancies:

FIRE SAFETY (FS)

SAFETY PARAMETERS

1301.6.4 Tenant and Dwelling Unit Separations

15

N/A

HVAC

X

1

2,500 sq. ft.

Corridor wall rating

Fire-resistance rating of vertical opening enclosures Type of HVAC system

B (Office, single tenant)

c)

0

0

1-story

2

2

2

1-story, e)

5

5

5

1301.6.8 Automatic Fire Detection

a)

4

4

4

1301.6.9 Fire Alarm System

a)

10

10

10

1301.6.10 Smoke Control

a)

****

0

0

1301.6.11 Means of Egress

c)

****

0

0

1301.6.12 Dead Ends

c)

****

2

2

****

14

14

****

1301.6.13 Maximum Exit Access Travel Distance 1301.6.14 Elevator Control 1301.6.15 Means of Egress Emergency Lighting 1301.6.16 Mixed Occupancies

1-story

0

0

a)

0

0

0

N/A - none

0

****

0

1301.6.17 Automatic Sprinklers

c)

0

0

0

1301.6.18 Standpipes

b)

0

****

0

N/A

0

2  0

0

34

50

50

1301.6.19 Incidental Accessory Occupancy Building score - total value * * * * No applicable value to be inserted.

Figure 13.18 The completed Table 1301.7 summary sheet for the Building 1 example when the existing M occupancy (a retail furniture store) is to be converted to a proposed B occupancy (a single-tenant real estate office). In this example, there are no NP values that must be addressed. © International Code Council

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TABLE 1301.9 EVALUATION FORMULAS FORMULA

T1201.7

T1201.9

SCORE

PASS

FS - MFS > 0

34

(FS)



30

(MFS)



4



ME - MME ≥ 0

50

(FS)



40

(MFS)



10



GS - MGS ≥ 0

50

(FS)



40

(MFS)



10



a. FS = Fire Safety

FAIL

MFS = Mandatory Fire Safety

ME = Measure of Egress

MME = Mandatory Means of Egress

GS = General Safety

MGS = Mandatory General Safety

Figure 13.19 The completed Table 1301.9 of the 2009 IEBC shown here indicates passing final scores for the example of an existing retail store (M occupancy) being converted to a single-tenant office (B occupancy) using the performance compliance method. No additional work is required by an NP score in Figure 13.18. © International Code Council

The mandatory safety score for various occupancy classifications was shown in Figure 13.16 in the previous example. The mandatory safety score for a Group M occupancy is subtracted from the totaled building score in each column. When the final score is zero or more, the building is in compliance. When the final score is less than zero, the building is not in compliance. The final scores for this building are Fire safety

34

(30)



4

Means of egress

50

(40)



10

General safety

50

(40)



10

These final scores are also reflected in the completed Table 1301.9 evaluation formulas for this example, seen in Figure 13.19. The building complies with all of the safety parameters for the proposed change to a single-tenant B occupancy. Due to the change from an M occupancy to a B occupancy, the number of required exits has decreased from two to one, and the addition of emergency power to egress lighting and exit signs is no longer required.

EXAMPLE BUILDING

1

SCOPE: Low-rise, Change of Occupancy, M to A-2

Now consider the previous one-story example building and see what happens when the occupancy changes to a denser use. The building remains the same 25-feet-wide by 100-feet-deep brick building that was described before. The construction remains Type III-B, as described in today’s codes. Figure 9.3 is still an applicable plan view of the building. Only the occupancy classification changes in this example. This time, the retail furniture store is to be replaced with a small restaurant (less than fifty persons total), perhaps a pizza or sandwich shop with a few tables, an A-2 occupancy. As a new Table 1301.7 summary sheet evaluation is filled out once again, it can be seen how the occupancy change affects some of the previous scores. The Table 1301.7 summary sheet for this proposed A-2 occupancy is shown in Figure 13.20 at the end of this example.

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Once again, starting with building height and area, Table 503 of the IBC, seen previously in Figure 13.2, is used to determine the permitted height (55 feet), the permitted number of stories (two), and the permitted area (9500 square feet) for the proposed A-2 occupancy in the Type III-B building. Now numerical scores can be computed. 6.1 Building height—Equations 13.1 and 13.2 are used to determine the height value that is to be entered into the Table 1301.7 summary sheet. The actual height of the building remains the same as that in the previous examples. Table 503 of the 2006 and 2009 editions of the IBC shows that two stories are allowed for an A-2 occupancy. In the 2006 IBC, this was a decrease from what it was for a B or an M occupancy, while the 2009 IBC shows that two stories are also allowed for the original M occupancy. Conveniently for this example, the height value will be the same for the proposed A-2 occupancy, whether the 2006 or 2009 editions are used. Notice how the allowable feet of height remains the same for the same construction type, but the allowable number of stories changes within the same type of construction for different occupancies. It is again the height value based on the number of stories that is the lesser value. In the case of the 2009 IBC, Table 503 has the same number of allowable stories (2) for both the existing and proposed occupancies, so the height value would be the same for the proposed A-2 occupancy as was derived for the M occupancy. This would be the same height value that was calculated using the 2006 codes for this A-2 occupancy, no matter how the equations are numbered. Putting the numbers for the new A-2 occupancy into the height equations gives

Height value, feet =

( AH) − (EBH) × CF 12.5

55 ft − 15 ft × 3.5 12.5 Height value, feet  11

Height value, feet =

(Equation 13-1) Height value, stories  (AS  EBS)  CF Height value, stories  (2 stories  1 story)  3.5 Height value, stories  3.5  4 (Equation 13-2, 2009 IEBC)

© International Code Council

This time, the building height value is well below the maximum score of +10, so the smaller value is used. Enter the height value based on stories, rounded to +4, on the summary sheet.

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6.2 Building area—The building area score is a function of the allowable and actual area per floor for a specific occupancy classification. Here, also, it is seen that the change in occupancy affects the scores. Again, there are no allowable increases for frontage or sprinklers. Using the 9500-sq ft allowable found in Table 503 of the IBC, the area equations are solved. A a = (1 + If + Is ) × A t A a = (1 + 0 + 0 ) × 9500 A a = 9500 (Equation 13-3, 2009 IEBC)

© International Code Council

From the allowable area per floor Aa, Equation 13.4 is solved for the area value.

Area valuei =

⎛ Actual area i Actual area a ⎞⎟⎤⎥ Allowable areai ⎡⎢ ⎟⎟ 1 − ⎜⎜⎜ +... + ⎜⎝ Allowable areai Allowable areaa ⎟⎠⎥⎥⎦ 1200 square feet ⎢⎢⎣

Area value =

9500 sf ⎡⎢ ⎛⎜ 2500 sf ⎞⎟⎤⎥ ⎟⎟ 1− ⎜ 1200 ⎢⎢⎣ ⎜⎜⎝ 9500 sf ⎠⎟⎥⎥⎦

Area value = 5 (Equation 13-4)

© International Code Council

This area value of +5 is a big change from area scores that were calculated for the other occupancies in the same building. Before the value is entered on the summary sheet, the maximum limit must be checked. The maximum permitted positive area value is 50 percent of the mandatory safety scores for the proposed occupancy per Table 1301.8, previously seen in the first example in Figure 13.16. This gives an area value of 0.5 × (21) = +10.5 for an A-2 occupancy category. The computed area value is less than this maximum, so the lesser value of +5 is entered on the Table 1301.7 summary sheet. 6.3 Compartmentation—The compartment size is still the single floor of 2500 square feet. For an A-2 occupancy, however, Table 1301.6.3, seen in Figure 13.4, shows the Category e compartment size of 2500 square feet or less has a score of only +18. This score is smaller than the previous examples, driven by the proposed A-2 occupancy. 6.4 Tenant and dwelling unit separations—When there is only one tenant, the tenant separation category is still Category c. Table 1301.6.4, seen in Figure 13.5 in a previous example, shows that the same Category c designation that was used before for a single-tenant building now has a different value for this A-2 occupancy. A score of -3 is entered into the summary sheet.

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6.5 Corridor walls—For this A-2 occupancy, a Category c condition with no corridors is still applicable, as permitted by Section 1014, of the 2009 IBC. The score for this condition is the same as before; enter 0 on the summary sheet. 6.6 Vertical openings—A change in occupancy makes no difference here. The value of +2 remains the same for this one-story building. 6.7 HVAC system—This score is not affected by a change in occupancy. Continue to use Category e for this one-story building. The score is a +5. 6.8 Automatic fire detection—This time, the score takes a hard hit in Table 1301.6.8 for the occupancy change to an A-2. Score a -25 for this A-2 building with no smoke detectors, a Category a—none. 6.9 Fire alarm systems—This building has no fire alarm system. This is still a Category a building, but in an A-2 occupancy Table 1301.6.0 the score is -10. 6.10 Smoke control—The building still has no smoke control; it is still a Category a—none. A score of zero is once again assigned to the last two columns in the Table 1301.7 summary sheet. 6.11 Means-of-egress capacity and number—With a change to an A-2 occupancy, care must be taken when determining the number of persons that may occupy this space. Rather than determining how many persons may occupy the kitchen space (200 square feet per person) and how many persons may occupy the dining space (15 square feet per person), the original assumption was that this is a dining establishment limited to fewer than fifty persons total, so the egress capacity and number has not changed. For example purposes, continue to rate this item as a Category c. Capacity of the means of egress is equal to or exceeds 125 percent of the required means-of-egress capacity and is in compliance for the minimum number of exits and the minimum required width dimensions. In an A-2 occupancy, the score is a +2, shown in the last two columns of the summary sheet—a very slight improvement over the other two occupancies that were previously examined. Depending on the condition of the rear exit, including door swing and latch type, this might even count as a Category d, where the number of exits provided exceeds the number of exits required by Section 1019 of the IBC, and they are located a distance apart from each other as specified in Section 1015 of the IBC. This would score as a +8 for this A-2 occupancy. Without knowing specific conditions, enter the +2 score for the Category c conditions on the summary sheet. 6.12 Dead ends—No change in score due to the change in occupancy. Score this building as a Category c—no dead ends, and enter the +2 into the last two columns of the summary sheet. 6.13 Maximum exit access travel distance—An A-2 occupancy has the same requirements for maximum unsprinklered travel distance as both the M and the B occupancies previously examined, as seen in Table 1016.1 of the 2009 IBC. The same exit distance of about 60 feet is used, and the maximum allowable travel distance (200 feet) has not changed due to an A-2 occupancy. Equation 13.6 still looks the

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same for this A-2 occupancy and the same score of +14 is used as in the previous examples. 6.14 Elevator controls—Once again, a score of zero is entered in all three columns of the summary sheet for this single-story building with no elevator. 6.15 Means-of-egress emergency lighting—Once again it is assumed that Category a conditions exist, with means-of-egress lighting and exit signs not provided with emergency power. This time, the A-2 occupancy has defined the number of persons to be fewer than fifty, so only one exit is required, per Table 1019.2 in the IBC. So, for this A-2 occupancy, enter a value of zero on the summary sheet. Just as was seen in the previous example with a change to a B occupancy, this A-2 occupancy does not require a system meeting the minimum standards for emergency power for meansof-egress lighting and exit signs to be provided, according to this performance compliance method. 6.16 Mixed occupancy—This building has only one occupancy group; in this example, it will be an A-2 occupancy. (The kitchen is considered accessory use to the assembly/dining use.) As a building without mixed occupancies, the value is zero. 6.17 Automatic sprinklers—This building does not have an automatic sprinkler system; nor are sprinklers required. It is classed as Category c—sprinklers are not required; none are provided. For this Category c building, the score for an A-2 occupancy is still 0, entered in the first and third columns of the summary sheet. In the second column, the score is divided by 2, but once again remains 0. 6.18 Standpipes—Again, there is no change in score due to the change in occupancy of this one-story building (with no standpipes), nor are they required. The building is classed as Category b, and a score of 0 is given. 6.19 Incidental use—In this building, there are no incidental uses, as defined by Section 508.2 of the IBC. Enter a score of 0 on the summary sheet. The individual values determined above for the existing building with a change to an A-2 occupancy are shown in the completed summary table shown in Figure 13.20. The value is the same in each column: fire safety, means of egress, and general safety, unless noted otherwise. The sum of the values in each column is determined. In this case, Fire safety

4

Means of egress

14

General safety

14

The mandatory safety score for various occupancy classifications was previously shown in Figure 13.16. The mandatory safety score for a Group A-2 occupancy is subtracted from the building score. The scores for this building are

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Fire safety

4

 (21)



25

Means of egress

14

 (32)



18

General safety

14

 (32)



18

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TABLE 1301.7 SUMMARY SHEET - BUILDING CODE Existing occupancy

M (Retail)

Proposed occupancy

Year building was constructed

1918

Number of stories

Type of construction

III-B

Area per Floor

Percentage of open perimeter increase

0

%

Completely suppressed:

Yes

No

X

Compartmentation:

Yes

No

X

Height in feet

N/A

Required door closers:

Yes

, serving number of floors

Automatic fire detection:

Yes

No

X

Type of location

Fire alarm system:

Yes

No

X

Type

Smoke control:

Yes

No

X

Type

Adequate exit routes:

Yes

No

Dead ends:

Maximum exit access travel distance

60’

Means-of-egress emergency lighting: Yes

No

15

No

X

N/A

HVAC

X

1

2,500 sq. ft.

Corridor wall rating

Fire-resistance rating of vertical opening enclosures Type of HVAC system

A-2 (Restaurant, < 50 persons)

X

1

Yes

No

X (None)

Elevator controls:

Yes

No

N/A

Mixed occupancies:

Yes

No

X

FIRE SAFETY (FS)

MEANS OF EGRESS (ME)

GENERAL SAFETY (GS)

1301.6.1 Building Height

4

4

4

1301.6.2 Building Area

5

5

5

≤ 2500 sf, e)

18

18

18

c)

0

0

0 0

SAFETY PARAMETERS

1301.6.3 Compartmentation 1301.6.4 Tenant and Dwelling Unit Separations 1301.6.5 Corridor Walls

c)

0

0

1-story

2

2

2

1-story, e)

5

5

5

1301.6.8 Automatic Fire Detection

a)

25

25

25

1301.6.9 Fire Alarm System

a)

10

10

10

1301.6.10 Smoke Control

a)

****

0

0

1301.6.11 Means of Egress

c)

****

2

2

1301.6.12 Dead Ends

c)

****

2

2

****

14

14

1301.6.6 Vertical Openings 1301.6.7 HVAC Systems

1301.6.13 Maximum Exit Access Travel Distance 1301.6.14 Elevator Control 1301.6.15 Means of Egress Emergency Lighting 1301.6.16 Mixed Occupancies

1-story

****

0

0

a)

0

0

0

N/A - none

0

****

0

1301.6.17 Automatic Sprinklers

c)

0

0

0

1301.6.18 Standpipes

b)

0

****

0

N/A

0

2  0

0

14

14

1301.6.19 Incidental Accessory Occupancy Building score - total value

4

* * * * No applicable value to be inserted.

Figure 13.20 The completed Table 1301.7 summary sheet for the Building 1 example, for the existing M occupancy (a retail furniture store) to be converted to a proposed A-2 occupancy (a small restaurant, fewer than fifty persons). In this example, the large negative scores indicate areas that are targets for improvement. © International Code Council

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TABLE 1301.9 EVALUATION FORMULAS FORMULA

T1201.7

T1201.9

SCORE

PASS

FAIL

FS - MFS > 0

4

(FS)



21

(MFS)



25



ME - MME ≥ 0

14

(FS)



32

(MFS)



18



GS - MGS ≥ 0

14

(FS)



32

(MFS)



18



a. FS = Fire Safety

MFS = Mandatory Fire Safety

ME = Measure of Egress

MME = Mandatory Means of Egress

GS = General Safety

MGS = Mandatory General Safety

Figure 13.21 The completed Table 1301.9 of the 2009 IEBC shown here indicates passing final scores for the example of an existing retail store (M occupancy) being converted to a proposed A-2 occupancy. In this example, there are failing final scores in all three categories of safety parameters—fire safety, means of egress, and general safety—indicating that improvements are necessary. © International Code Council

These building scores and mandatory scores for the three groups of safety parameters are shown in the evaluation formulas of Table 1301.9, seen in Figure 13.21. The three resulting scores are all negative numbers. The building does not comply with any of the safety parameters for the proposed change from an M occupancy to an A-2 occupancy. To bring the building into compliance, the weakest scores, namely the -25 for automatic fire detection and the -10 for fire alarm system, are likely target areas for improvement. If the rear door also served the dining area as a second exit, perhaps only the automatic fire detection would need to be addressed. This exercise using the performance compliance method points out very specifically what the building lacks when considering an occupancy change from an M occupancy to an A-2 establishment.

High-rise Building

EXAMPLE BUILDING

2

High-rise, Thirteenstory Office Building SCOPE: Existing High-rise

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For this analysis, we are using the thirteen-story building described in Chapter 9 as it was originally constructed. Many changes and safety improvements have, no doubt, been made over time. The building was also selected because it has so many deficiencies, thus showing most of the safety issues that are likely to appear in highrise buildings of this age. As before, each building safety parameter is evaluated through a review of the in-place system or by computing a score based on area, height, or travel distance. The score for each category is entered in a summary sheet, Table 1301.7 of the IEBC. This blank form is shown in Figure 13.22.

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TABLE 1301.7 SUMMARY SHEET - BUILDING CODE Existing occupancy

Proposed occupancy

Year building was constructed

Number of stories

Type of construction

Area per Floor

Percentage of open perimeter increase

%

Completely suppressed:

Yes

No

Compartmentation:

Yes

No

Height in feet

Corridor wall rating Required door closers: Yes

No

Fire-resistance rating of vertical opening enclosures Type of HVAC system

, serving number of floors

Automatic fire detection:

Yes

No

Type of location

Fire alarm system:

Yes

No

Type

Smoke control:

Yes

No

Type

Adequate exit routes:

Yes

No

Dead ends:

Yes

No

Elevator controls:

Yes

No

Mixed occupancies:

Yes

No

Maximum exit access travel distance Means-of-egress emergency lighting: Yes

SAFETY PARAMETERS

No

FIRE SAFETY (FS)

MEANS OF EGRESS (ME)

GENERAL SAFETY (GS)

1301.6.1 Building Height 1301.6.2 Building Area 1301.6.3 Compartmentation 1301.6.4 Tenant and Dwelling Unit Separations 1301.6.5 Corridor Walls 1301.6.6 Vertical Openings 1301.6.7 HVAC Systems 1301.6.8 Automatic Fire Detection 1301.6.9 Fire Alarm System 1301.6.10 Smoke Control

****

1301.6.11 Means of Egress

****

1301.6.12 Dead Ends

****

1301.6.13 Maximum Exit Access Travel Distance

****

1301.6.14 Elevator Control

****

1301.6.15 Means of Egress Emergency Lighting 1301.6.16 Mixed Occupancies 1301.6.17 Automatic Sprinklers 1301.6.18 Standpipes

****

1301.6.19 Incidental Accessory Occupancy

2 

Building score - total value * * * * No applicable value to be inserted.

Figure 13.22 Table 1301.7, 2009 IEBC, is the summary table used to tabulate the quantitative values given to numerous parameters in three categories of safety concern. © International Code Council

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TABLE 503 ALLOWABLE BUILDING HEIGHTS AND AREASa Building height limitations shown in feet above grade plane. story limitations shown as stories above grade plane. Building area limitations shown in square feet as determined by the definition of “Area, building,” per story TYPE OF CONSTRUCTION TYPE II TYPE III TYPE IV A B A B HT 65 55 65 55 65

TYPE I HEIGHT (feet)

A UL

B 160

S A S A S A

UL UL UL UL UL UL

11 UL 11 UL 11 UL

STORIES (S) AREA (A)

GROUP A-2 B M

TYPE V A B 50 40

3 15,500 5 37,500 4 21,500

2 9,500 3 23,000 2 12,500

3 14,000 5 28,500 4 18,500

2 9,500 3 19,000 2 12,500

3 15,000 5 36,000 4 20,500

2 11,500 3 18,000 3 14,000

1 6,000 2 9,000 1 9,000

For SI: 1 foot = 301.8 mm, 1 square foot = 0.0929 m2. A = building area per story, S = stories above grade plane, UL = Unlimited, NP = Not permitted. a. See the following sections for general exceptions to Table 503: 1. Section 504.2. Allowable building height and story increase due to automatic sprinkler system installation. 2. Section 506.2. Allowable building area increase due to street frontage. 3. Section 506.3. Allowable building area increase due to automatic sprinkler system installation. 4. Section 507. Unlimited area buildings. b. For open parking structures, see Section 406.3. c. For private garages, see Section 406.1. d. See Section 415.5 for limitations.

 Figure 13.23 Selected portions of Table 503 heights and areas of the 2009 IBC are shown, providing the basic allowable height and area per story for a specific occupancy group and type of construction. Circled values are used in the three Building 2 examples using the performance compliance method. © International Code Council

 Figure 13.24 Table 1301.6.6(2) of the 2009 IEBC provides a factor used to express construction type in the performance compliance method. © International Code Council

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Building height and area are the first items considered. In this case, since the building is Type I-A, the permitted height and area are unlimited, as indicated in Table 503 of the IBC, shown in Figure 13.23. For consistency, the category numbering used here is similar to the numbering in IEBC Section 1301.6. 6.1 Building height—A numerical score is computed based on the allowable height, the existing height, and a construction-type factor (CF). There are two ways to determine the height score, by the building height in feet, found in Equation 13.1, or the building height in number of stories, found in Equation 13.2. The equations include a construction-type factor (CF) that is based on the construction type, Type I-A in this case. (See Figure 13.24.)

TABLE 1301.6.6(2) CONSTRUCTION-TYPE FACTOR F A C T O R

TYPE OF CONSTRUCTION IA

IB

IIA

IIB

IIIA IIIB

IV

VA

VB

1.2

1.5

2.2

3.5

2.5

2.3

3.3

7

3.5

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187

With values specific to this example building, the formulas are Height value, feet =

( AH) − (EBH) × CF 12.5

UL − 150 ft × 1.2 12.5 Height value, feet  UL

Height value, feet =

(Equation 13-1) Height value, stories  (AS  EBS)  CF Height value, stories  (UL  13 stores)  1.2 Height value, stories  UL (Equation 13-2, 2009 IEBC)

© International Code Council

There is a maximum limit to what score may be given for the height value. In this example, use the maximum score of +10. 6.2 Building area—The building area score is a function of the allowable and actual area per floor for a specific occupancy classification. This is then compared to that permitted by the International Building Code. It is a somewhat more complex calculation than that for the height value. In the 2006 IEBC, the area value was computed using no less than four equations. In the 2009 IEBC, that computation has been simplified into two equations that are shown here. Once the area value is derived, it is entered into the summary sheet. Following the equations found in the 2009 IEBC, the allowable area for a building of this type and occupancy is determined. The code permits increases in allowable area based on frontage on a public way. There are also increases for automatic sprinklers. Starting with Equation 13.3, the allowable area per story (Aa) is calculated using the tabulated allowable area value (At) found in Table 503 of the IBC, with increase factors for frontage (If) and for sprinklers (Is). Aa  (1  If  Is)  At Aa  (1  0  0)  UL Aa  UL (Equation 13-3, 2009 IEBC)

© International Code Council

Using the allowable area per floor (Aa) and the actual area per floor, Equation 13.4 is solved for the area value and entered into the summary sheet. In this example, though, the allowable area is unlimited (UL). So Equation 13.4 for the area value looks like this: Area valuei =

⎛ Actual area i Allowable areai ⎡⎢ Actual area a ⎞⎟⎤⎥ ⎟⎟ 1 − ⎜⎜⎜ +... + ⎜⎝ Allowable areai 1200 square feet ⎢⎢⎣ Allowable areaa ⎟⎠⎥⎥⎦

Area value = UL (Equation 13-4)

© International Code Council

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TABLE 1301.6.3 COMPARTMENTATION VALUES CATEGORIES

OCCUPANCY

a Compartment size equal to or greater than 15,000 square feet

b Compartment size of 10,000 square feet

c Compartment size of 7,500 square feet

d Compartment size of 5,000 square feet

e Compartment size of 2,500 square feet or less

A-1, A-3

0

6

10

14

18

A-1

0

4

10

14

18

A-4, B, E, S-2

0

5

10

15

20

F, M, R, S-1

0

4

10

16

22

For SI: 1 square foot = 0.0929 m 2.

Figure 13.25 Table 1301.6.3 of the 2009 IEBC provides a quantitative value to express the net area created by fire barrier walls with a fireresistance rating of not less than 2 hours. Where the building is not divided into more than one compartment, the compartment size shall be taken as the total floor area on all floors. © International Code Council

Before the results from Equation 13.4 are entered into the summary sheet, though, the maximum permitted positive area value must be checked. The maximum permitted positive area value is 50 percent per Table 1301.8, seen in Figure 13.41 at the end of this example. This gives the maximum permitted area value of 0.5 × (30) = +15 for a B occupancy category. Enter +15 on the Table 1301.7 summary sheet. As seen in previous examples, it is important to keep track of the positive and negative signs on the summary sheet. 6.3 Compartmentation—Compartments in a building limit the spread of fire by enclosing areas with walls as well as the floors and ceiling assemblies. In buildings of this type, the walls are often hollow clay tile with a 2-hour fire-resistance rating. The floors of the building are reinforced concrete, again a 2-hour fire-resistance rating. The compartment size is a single floor of 10,000 square feet. For a B occupancy, the compartment size of 10,000 square feet is a Category b with a score of +5 found in Table 1301.6.3, seen here in Figure 13.25. Had there been additional compartmentation, a higher score would have been obtained.

TABLE 1301.6.4 SEPARATION VALUES CATEGORIES OCCUPANCY

a

b

c

d

e

A-1

0

0

0

0

1

A-2

5

3

0

1

3

R

4

2

0

2

4

A-3, A-4, B, E, F, M, S-1

4

3

0

2

4

S-2

5

2

0

2

4

Figure 13.26 Table 1301.6.4 of the 2009 IEBC is used to quantify the amount of separation between tenants in the building being evaluated. © International Code Council

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6.4 Tenant and dwelling unit separations—Separation, like compartmentation, limits the spread of fire between spaces occupied by different tenants. The fire resistance of the walls and floors between tenants is evaluated here. It was assumed that the walls between tenants had a 1-hour fire-resistance rating and the floor was 2 hours as considered in the previous section. In this case, it was determined that the conditions were a Category c—fire partitions with a 1-hour or greater rating and floor assemblies with a greater than 1-hour but less than 2-hour rating. Table 1301.6.4, seen in Figure 13.26 in this example, gives a score of zero. Additional investigation might show that the floor has a 2-hour rating, which would raise the category to a d and raise the score to a +2. Until that can be confirmed, enter a score of zero on the summary sheet.

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Performance Compliance Method Examples

TABLE 1301.6.5 CORRIDOR WALL VALUES

189

TABLE 1301.6.6(1) VERTICAL OPENING PROTECTION VALUE PROTECTION

CATEGORIES

VALUE

OCCUPANCY

a

b

c

None (unprotected opening)

-2 times number of floors connected

A-1

10

4

0

2

Less than 1 hour

-1 times number of floors connected

A-2

30

12

0

2

1 to less than 2 hours

1

A-3, F, M, R, S-1

7

3

0

2

2 hours or more

2

A-4, B, E, S-2

5

2

0

5

a

d

a

a. Corridors not providing at least one-half the travel distance for all occupants on a floor shall use Category b.

Figure 13.27 Table 1301.6.5, 2009 IEBC, provides the corridor wall value to be entered into the summary sheet of Table 1301.7. © International Code Council

Figure 13.28 Table 1301.6.6(1) of the 2009 IEBC provides the vertical opening protection value that is used in Equation 13.5 to obtain a vertical opening value, which is to be entered into the summary sheet of Table 1301.7. © International Code Council

6.5 Corridor walls—Corridor walls need to be evaluated to determine whether they permit the spread of fire into the corridor. This is of special concern since building occupants are forced into a specific path and confined space. The original building would have had glass transoms over the doors, often glazing in the door, and sometimes a louvered opening near the base of the door, each permitting the fire to enter the corridor. Further, there may have been a wood wainscot in the corridor. This was determined to be a Category a condition with no fire partitions, incomplete fire partitions, no doors, or doors not self-closing. Table 1301.6.5, seen here in Figure 13.27, gives the score for this condition as -5. 6.6 Vertical openings—As discussed earlier, vertical openings, including stairways and shafts, act as chimneys, permitting smoke to move through the building. Many jurisdictions have adopted retroactive provisions to require enclosure of stair shafts. The rating formula, Equation 13.5, is based on the number of stories that the open stairway connects, in this example, thirteen. It also considers the type of construction reflected in the protection value (PV), and also in the construction factor (CF). This building has an open stairway, which is a significant hazard. There are also elevator shafts in the building. For this analysis, Table 1301.6.6(1), seen here in Figure 13.28, gives the protection value as –2 times the number of floors connected, or PV = –2 per story × 13 stories = –26. Table 1301.6.6(2), seen earlier in this example in Figure 13.24, gives the construction factor (CF) of 1.2 for this Type I-A construction. These factors are inserted into Equation 13.5 to get the resulting score of -31.2. Round this number to the nearest integer and enter -31 on the summary sheet. VO = PV × CF VO = −26 × 1.2 VO = −31.2 ≈ −31 (Equation 13-5)

© International Code Council

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International Existing Building Code Performance Compliance Method

TABLE 1301.6.8 AUTOMATIC FIRE DETECTION VALUES

TABLE 1301.6.9 FIRE ALARM SYSTEM VALUES

CATEGORIES

CATEGORIES

OCCUPANCY

a

b

c

d

e

OCCUPANCY

a

ba

c

d

A-1, A-3, F, M, R, S-1

10

5

0

2

6

A-1, A-2, A-3, A-4, B, E, R

10

5

0

5

A-2

25

5

0

5

9

F, M, S

0

5

10

15

A-4, B, E, S-2

4

2

0

4

8

a. For buildings equipped throughout with an automatic sprinkler system, add 2 points for activation by a sprinkler water-flow device.

Figure 13.29 Table 1301.6.8 of the 2009 IEBC provides a value that describes the smoke-detection capability based on the location and operation of automatic fire detectors in accordance with Section 907 of the IBC. © International Code Council

Figure 13.30 Table 1301.6.9 of the 2009 IEBC is used to evaluate how well the fire alarm system meets Section 907 of the IBC. © International Code Council

TABLE 1301.6.10 SMOKE CONTROL VALUES CATEGORIES OCCUPANCY

a

b

c

d

e

f

A-1, A-2, A-3

0

1

2

3

6

6

A-4, E

0

0

0

1

3

5

B, M, R

0

2a

3a

3a

3a

4a

F, S

0

2a

2a

3a

3a

3a

a. This value shall be 0 if compliance with Category d or c in Section 1201.6.8 1 has not been obtained.

Figure 13.31 Smoke control values are given here in Table 1301.6.10 of the 2009 IEBC. © International Code Council

6.7 HVAC system—Ductwork for heating and cooling systems will also move smoke through the building. Since the original building had radiators for heat and openable windows for “cooling,” it was classed as Category e, a central boiler without ductwork connecting two or more stories. The score is a +5. 6.8 Automatic fire detection—Smoke detectors will notify occupants of a fire, permitting a faster exit than waiting for other notifications. In this building, there were no smoke detectors, placing it in Category a—none. Table 1301.6.8, seen in Figure 13.29, gives the score as -4 for this occupancy.

6.9 Fire alarm systems—It is assumed that the building has a manual fire alarm system with a pull box at one or two locations on each floor. However, a qualifying fire alarm system with manual fire alarm boxes would also need to have visible and audible alarms and emergency power. The fire alarm in this example is Category a—none. A score of –10 is found in Table 1301.6.9, seen in Figure 13.30; enter the score on the summary sheet. 6.10 Smoke control—Like the vertical shafts, the control of smoke is a principal safety element. While windows will help exhaust smoke, the lack of an automatic fire sprinkler system and an enclosed stairway resulted in the structure receiving a Category a—none, with a score of zero found in Table 1301.6.10, seen in Figure 13.31. Enter the score in the last two columns of the Table 1301.7 summary sheet. 6.11 Means-of-egress capacity and number—The means-of-egress capacity and number need to be evaluated. In the 2009 IEBC, Table 1301.6.11(1) is provided to clarify exactly how the required egress width (capacity) is to be calculated. This table,

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Performance Compliance Method Examples

TABLE 1301.6.11(1) EGRESS WIDTH PER OCCUPANT SERVED WITH SPRINKLER SYSTEMa

WITHOUT SPRINKLER SYSTEM Stairways (Inches per occupancy)

Other egress components (Inches per occupancy)

Stairways (Inches per occupancy)

Other egress components (Inches per occupancy)

0.3

0.2

0.2

0.15

Hazardous: H-1, H-2, H-3, H-4

Not permitted

Not permitted

0.3

0.2

Institutional: I-2

Not permitted

Not permitted

0.3

0.2

OCCUPANCY Occupancies other than those listed below

For SI: 1 inch = 25.4 mm. a. Buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.1.1 or 903.3.1.2.

TABLE 1301.6.11(2) MEANS OF EGRESS VALUES CATEGORIES a

OCCUPANCY

a

b

c

d

e

A-1, A-2, A-3, A-4, E

10

0

2

8

10

M

3

0

1

2

4

B, F, S

1

0

0

0

0

R

3

0

0

0

0

a. The values indicated are for buildings six stories or less in height. For buildings over six stories above grade plan, add an additional -10 points.

Figure 13.32 Table 1301.6.11 of the 2009 IEBC provides a value that describes means-of-egress capacity and the number of exits available to the building occupants. © International Code Council

which is similar to, but not exactly like, that found in the 2006 IBC, can be seen in Figure 13.32. In this building, there is one stairway and a fire escape, providing two means of egress. Corridor width (capacity) meets current code and is complying. This parameter is rated Category a, compliance by means of a fire escape. Table 1301.6.11(2), seen in Figure 13.32, provides the score for this parameter. Enter the score of -1 in the last two columns of the summary sheet.

TABLE 1301.6.12 DEAD-END VALUES CATEGORIESa OCCUPANCY

a

b

c

A-1, A-3, A-4, B, F, M, R, S

2

0

2

A-2, E

2

0

2

a. For dead-end distances between categories, the dead end value shall be obtained by linear interpolation.

Figure 13.33 Table 1301.6.12 of the 2009 IEBC provides

6.12 Dead ends—Corridor dead ends can trap occupants values that define dead-end conditions in spaces that are in an emergency. Since there is a continuous path from the required to be served by more than one means of egress. interior stairway to the fire escape, any dead ends would be © International Code Council limited in length. This was deemed to be a Category b, dead ends of 20 feet to no more than 50 feet. Find the score in Table 1301.6.12, seen in Figure 13.33. The score entered in the last two columns for this example is zero.

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International Existing Building Code Performance Compliance Method

6.13 Maximum exit access travel distance—Travel distance to the exit is limited by the building code. Travel distance in this building includes the distance along the corridor, the length of the stair transit, and the distance from the stair to the street exit. This building had an exit distance of about 75 feet on a floor to the stairs, plus several hundred feet of travel down the twelve flights of stairs plus landings. The total exit length was determined to be about 425 feet to the exterior. The allowable travel distance is 200 feet, found in Table 1016.1 of the IBC. By inserting this actual travel distance, as well as the allowable travel distance, into Equation 13.6, the score for maximum exit access travel distance can be found. Points = 20 ×

Maximum allowable travel distance − Maximum actual travel distance Maximum allowable travel distance

0× Points = 20

200 ft − 425 ft 200 ft

Points = −22.5 ≈ −23

(Equation 13-6)

© International Code Council

Round the number to the nearest integer, and enter -23 in the last two columns of the summary sheet. Building codes today allow different travel distance to exits, depending on whether the building is fire sprinklered or not. 6.14 Elevator controls—Elevator controls permit manual operation by firefighters to permit the elevator to go to a specific floor above or below the fire floor for firesuppression action. This building does not have such controls. This 13-story building also has elevator travel of more than 25 feet above the primary level of elevator access for emergency fire/rescue personnel. Such a condition is considered a Category b, any elevator without Phase I and II recall, and has a value of NP (not permitted) found in Table 1301.6.14, seen in Figure 13.34. Regardless of the score, the building will have to be retrofitted as part of this project. Enter NP in all three columns of the summary sheet.

TABLE 1301.6.14 ELEVATOR CONTROL VALUES CATEGORIES a

b

c

d

Less than 25 feet of travel above or below the primary level of elevator access for emergency fire-fighting or rescue personnel

2

0

0

2

Travel of 25 feet or more above or below the primary level of elevator access for emergency fire-fighting or rescue personnel

4

NP

0

4

ELEVATOR TRAVEL

Figure 13.34 Table 1301.6.14 of the 2009 IEBC provides values that define elevator control conditions. © International Code Council

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For SI: 1 foot = 304.8 mm. NP = Not permitted.

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Performance Compliance Method Examples

TABLE 1301.6.15 MEANS-OF-EGRESS EMERGENCY LIGHTING VALUES NUMBER OF EXITS REQUIRED BY SECTIONS 1018.1 AND 1018.2 OF THE INTERNATIONAL BUILDING CODE

CATEGORIES a

b

c

Two or more exits

NP

0

4

0

1

I

Minimum of one exit

193

TABLE 1301.6.16 MIXED OCCUPANCY VALUES* CATEGORIES OCCUPANCY

a

b

c

A-l, A-2, R

10

0

10

A-3, A-4, B, E, F, M, S

5

0

5

NP = Not permitted.

a. For fire-resistance ratings between categories, the value shall be obtained by linear interpolation.

Figure 13.35 Table 1301.6.15 of the 2009 IEBC provides values that express the presence and reliability of means-of-egress emergency lighting. A rating of NP (not permitted) must be corrected, even if the final scores are passing. © International Code Council

Figure 13.36 Table 1301.6.16 of the 2009 IEBC supplies the mixed-occupancy value to be scored on the Table 1301.7 summary sheet. For buildings without mixed occupancies, the value is zero. © International Code Council

6.15 Means-of-egress emergency lighting—An illuminated exit path is critical. When this building was constructed, this was not required. For this discussion, it is assumed not present. Category a is means-of-egress lighting and exit signs not provided with emergency power. Table 1301.6.15, seen in Figure 13.35, gives a value of NP, not permitted. A system meeting the minimum standards will have to be provided regardless of the total building score. Enter NP in the last two columns of the summary sheet.

TABLE 1301.6.17 SPRINKLER SYSTEM VALUES CATEGORIES a

a

b

c

d

e

f

A-1, A-3. F, M, R, S-1

6

3

0

2

4

6

A-2

4

2

0

1

2

4

A-4, B, E, S-2

12

6

0

3

6

12

OCCUPANCY

a

a. These options cannot be taken if Category a in Section 1301.6.18 is used.

Figure 13.37 Fire sprinkler values given in Table 1301.6.17 of the

2009 IEBC are used to express the ability to suppress a fire based 6.16 Mixed occupancy—This building has only on the installation of an automatic sprinkler system in accordance with one occupancy group, B. But if there were a dining use on the first floor, special consideration Section 903.3.1.1 of the IBC. © International Code Council would be necessary. Using Table 1301.6.16, seen in Figure 13.36, find the score for the conditions present. As a building without mixed use, it is considered a Category b and is given a score of zero. Enter the score in the first and third columns of the summary sheet.

6.17 Automatic sprinklers—This building does not have an automatic sprinkler system. It is classed as Category a—noncompliant or nonexisting sprinklers. Use Table 1301.6.17, seen in Figure 13.37, to find the score. Enter the score of -12 in the first and third columns of the summary sheet. In the second column, divide -12 by 2 and enter a score of -6. 6.18 Standpipes—Standpipes, pipes that permit the fire department to pump water to each story, were installed when this building was constructed and are still serviceable. This is classified as Category c—standpipes required and provided. Table 1301.6.18, seen in Figure 13.38, gives the score for this category. Enter the score of +6 in all three columns of the summary sheet. 6.19 Incidental use—Incidental uses, such as conference rooms, boiler rooms, or storage rooms larger than 100 square feet, as described in Section 508.2 of the

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International Existing Building Code Performance Compliance Method

Figure 13.38 Table 1301.6.18 of the 2009 IEBC gives a quantitative value to the ability to initiate an attack on a fire by making the supply of water available through standpipes. © International Code Council

TABLE 1301.6.18 STANDPIPE SYSTEM VALUES CATEGORIES OCCUPANCY

a

a

b

c

d

A-l, A-3, F, M, R, S-1

6

0

4

6

A-2

4

0

2

4

A-4, B, E, S-2

12

0

6

12

a. This option cannot be taken if Category a or Category b in Section 1301.6.17 is used.

TABLE 1301.6.19 INCIDENTAL ACCESSORY OCCUPANCY AREA VALUES* PROTECTION REQUIRED BY TABLE 508.2.5 OF THE INTERNATIONAL BUILDING CODE

PROTECTION PROVIDED

None

1 hour

AFSS

AFSS with SP

1 hour and AFSS

2 hours

2 hours and AFSS

2 hours and AFSS

1

3

2

2

1

2

0

2 hours, or 1 hour and AFSS

3

2

1

1

0

0

0

1 hour and AFSS

3

2

1

1

0

1

0

1 hour

1

0

1

1

0

0

1 hour, or AFSS with SP

1

0

1

1

0

0

0

AFSS with SP

1

1

1

1

0

1

0

1 hour or AFSS

1

0

0

0

0

0

0

a. AFSS = Automatic fire suppression system; SP = Smoke partitions (see IBC Section 508.2.5). Note: For Table 1301.7, see page 68.

Figure 13.39 Table 1301.6.19 of the 2009 IEBC is used to evaluate the protection of incidental use areas in accordance with Section 508.2 of the IBC. If there are no specific occupancy areas in the building or the fire area being evaluated, the value used shall be zero. © International Code Council

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IBC, might be within reasonable expectation in this building and may be located in different areas of buildings. The separation and fire sprinklering of such spaces will provide a different score for each case. In this example, it is assumed that there are no such areas of incidental uses that would trigger a negative score, as described in Table 1301.6.19, seen in Figure 13.39. Enter a score of zero in the summary sheet. At this time, the individual values for the existing building determined above have been entered into the summary sheet in Figure 13.40. The value for each parameter is the same in each column: fire safety, means of egress, and general safety, unless noted otherwise. The sum of the values in each column is calculated and entered as the ”building score—total value.” In this example, the totals are Fire safety

21

Means of egress

39

General safety

45

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Performance Compliance Method Examples

195

TABLE 1301.7 SUMMARY SHEET - BUILDING CODE Existing occupancy

B

Proposed occupancy

Year building was constructed

1920

Number of stories

Type of construction

I-A

Area per Floor

Percentage of open perimeter increase

16.7

Completely suppressed:

Yes (No sprinklers) No

Compartmentation:

Yes

No

% X

Yes

Fire alarm system:

Yes

Smoke control:

Yes

Required door closers:

Adequate exit routes:

Yes

X

Maximum exit access travel distance

Yes

X

X

Type X

N/A

Manual pull boxes & alarm

Type

N/A

Dead ends:

425’ (open stairs) No

1

Type of location

No

Means-of-egress emergency lighting: Yes

No

Open stairway - N/R

No No

150

N/R openings

, serving number of floors No

X

Height in feet

X

Radiators

Automatic fire detection:

13

10,000 sq. ft.

Corridor wall rating

Fire-resistance rating of vertical opening enclosures Type of HVAC system

B

X (20')

Yes

Elevator controls: Yes

X

Mixed occupancies:

No No X (no recall Phase I or II)

Yes

No

X

FIRE SAFETY (FS)

MEANS OF EGRESS (ME)

GENERAL SAFETY (GS)

1301.6.1 Building Height

10

10

10

1301.6.2 Building Area

15

15

15

SAFETY PARAMETERS

1301.6.3 Compartmentation

b)

5

5

5

1301.6.4 Tenant and Dwelling Unit Separations

c)

0

0

0

1301.6.5 Corridor Walls 1301.6.6 Vertical Openings

a)

5

5

5

N/R

31

31

31

1301.6.7 HVAC Systems

e)

5

5

5

1301.6.8 Automatic Fire Detection

a)

4

4

4

1301.6.9 Fire Alarm System

a)

10

10

10

1301.6.10 Smoke Control

a)

****

0

0

1301.6.11 Means of Egress

a)

****

1

1

1301.6.12 Dead Ends

b)

****

0

0

****

23

23

1301.6.13 Maximum Exit Access Travel Distance 1301.6.14 Elevator Control

b)

****

NP

NP

1301.6.15 Means of Egress Emergency Lighting

a)

0

NP

NP

0

****

a)

12

c)

6

N/A

0

1301.6.16 Mixed Occupancies 1301.6.17 Automatic Sprinklers 1301.6.18 Standpipes 1301.6.19 Incidental Accessory Occupancy Building score - total value

21

0

6

12

6

6

ⴜ2 ⴝ 0 39

0 45

* * * * No applicable value to be inserted.

Figure 13.40 The completed Table 1301.7 summary sheet for the Building 2 example, for the existing B occupancy office building (as-is conditions). The NP (not permitted) rating for the elevator control parameter and the means-of-egress emergency lighting parameter requires work be done to improve these conditions, no matter what the other scores are. © International Code Council

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TABLE 1301.8 MANDATORY SAFETY SCORESa OCCUPANCY

FIRE SAFETY (MFS)

MEANS OF EGRESS (MME)

GENERAL SAFETY (MGS)

A-1

20

31

31

A-2

21

32

32

A-3

22

33

33

A-4, E

29

40

40

B

30

40

40

F

24

34

34

M

23

40

40

R

21

38

38

S-1

19

29

29

S-2

29

39

39

a. MFS = Mandatory Fire Safety MME = Mandatory Means of Egress MGS = Mandatory General Safety

Figure 13.41 Table 1301.8 of the 2009 IEBC provides mandatory scores that the building must meet or exceed in the performance compliance method. © International Code Council

The mandatory safety score for various occupancy classifications is shown in Table 1301.8, seen here in Figure 13.41. The mandatory safety score for a Group B occupancy is subtracted from the building score. Where the final score is zero or more, the building is in compliance. Where the final score is less than zero, the building is not in compliance. The scores for this building are Fire safety

21

 (30)



51

Means of egress

39

 (40)



79

General safety

45

 (40)



85

These building scores and mandatory scores for the three groups of safety parameters can also be entered into the evaluation formulas of Table 1301.9, seen in Figure 13.42. In all three areas of concern, negative final scores indicate that this building does not comply with any of the safety parameters. How can this building be made to comply? Looking at the scores, first focus might be on the major markdowns. It is obvious that the unenclosed stairway is a major factor with a value of -31. Revising the stairway would raise the score, but may not completely eliminate the negative rating. Stairway enclosure would also reduce the travel distance to an exit, because travel distance is computed only to the enclosed stairway, not all the

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TABLE 1301.9 EVALUATION FORMULAS FORMULA

T1201.7

FS - MFS > 0

21

(FS)



30

(MFS)



51



ME - MME ≥ 0

39

(FS)



40

(MFS)



79



GS - MGS ≥ 0

45

(FS)



40

(MFS)



85



a. FS = Fire Safety

T1201.9

SCORE

PASS

FAIL

MFS = Mandatory Fire Safety

ME = Measure of Egress

MME = Mandatory Means of Egress

GS = General Safety

MGS = Mandatory General Safety

Figure 13.42 Table 1301.9 of the 2009 IEBC shows the findings and the differences between the total building scores, found at the bottom of the summary sheet in Figure 13.40, and the mandatory building scores, from Figure 13.41. Final scores of less than zero indicate a failing score. Any values of NP (not permitted) that were scored on the Table 1301.7 summary sheet must be corrected in addition to any other corrections to be made. © International Code Council

way to the street. But those improvements would not be sufficient to raise the final score (after subtracting the mandatory score from the building score) to a positive number. Therefore, additional improvements must be found to bring up the final scores. Other alternatives to consider would include the addition of automatic sprinklers. This would result in the value going from a -12 to a +6 for that parameter. The addition of the automatic sprinkler system would also have positive effects on the smoke control score, raising it up to zero for Category b when exterior windows are considered. A fire alarm system that would work in conjunction with the new automatic sprinkler system would revise the original score of -10 for that parameter to zero. With the addition of automatic fire sprinklers that work in conjunction with the fire alarm system, an enclosed stairway, and the mandatory elevator controls and emergency exit lighting, the score becomes Fire safety

39

 (30)



9

Means of egress

47

 (40)



7

General safety

50

 (40)



10

The completed summary sheet for this proposed work is shown in Figure 13.43, and the evaluation formulas are shown completed in Figure 13.44. These changes would make the building compliant. They also resolve one of the major causes of death in fire, an unenclosed stairway. As noted earlier, regardless of the score, fire department elevator controls and means-of-egress emergency lighting must be corrected under any approach.

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TABLE 1301.7 SUMMARY SHEET - BUILDING CODE Existing occupancy

B

Proposed occupancy

Year building was constructed

1920

Type of construction

I-A

B

Number of stories Area per Floor

Percentage of open perimeter increase

16.7

%

13

Height in feet

150

10,000 sq. ft.

Corridor wall rating

N/R doors

(full auto, sprinklers)

Completely suppressed:

Yes

X

No

Compartmentation:

Yes

X

No

Required door closers:

Fire-resistance rating of vertical opening enclosures Type of HVAC system

Yes

, serving number of floors

Yes

Fire alarm system:

Yes

X

No

Type

Smoke control:

Yes

X

No

Type

Adequate exit routes:

Yes

X

No

Dead ends: X (20’)

Yes

Elevator controls:

Yes

Mixed occupancies:

Yes

Means-of-egress emergency lighting: Yes

X

1

Automatic fire detection:

Maximum exit access travel distance

Type of location

123’ X

X

1-hr (lobby @ 1st floor)

(E) Radiators No

No

No

N/A Per Sec. 907, IBC Auto. sprinklers, exterior windows No X

No No

X

FIRE SAFETY (FS)

MEANS OF EGRESS (ME)

GENERAL SAFETY (GS)

1301.6.1 Building Height

10

10

10

1301.6.2 Building Area

15

15

15

5

5

5

SAFETY PARAMETERS

1301.6.3 Compartmentation

b)

1301.6.4 Tenant and Dwelling Unit Separations

c)

0

0

0

1301.6.5 Corridor Walls

a)

5

5

5

1-hr

1

1

1

1301.6.7 HVAC Systems

1301.6.6 Vertical Openings

e)

5

5

5

1301.6.8 Automatic Fire Detection

a)

4

4

4

1301.6.9 Fire Alarm System

c)

0

0

0

1301.6.10 Smoke Control

b)

****

0

0

1301.6.11 Means of Egress

a)

****

1

1

1301.6.12 Dead Ends

b)

****

0

0

****

12

12

****

0

0

1301.6.13 Maximum Exit Access Travel Distance 1301.6.14 Elevator Control

c)

1301.6.15 Means of Egress Emergency Lighting

b)

1301.6.16 Mixed Occupancies

0

0

0

0

****

0

1301.6.17 Automatic Sprinklers

e)

6

3

6

1301.6.18 Standpipes

c)

6

6

6

N/A

0

2  0

0

39

47

50

1301.6.19 Incidental Accessory Occupancy Building score - total value * * * * No applicable value to be inserted.

Figure 13.43 The completed Table 1301.7 summary sheet for the Building 2 example, with minimal improvements to the existing B occupancy office building to achieve passing final scores. The addition of a new stair enclosure and automatic sprinklers, combined with the mandatory emergency power for means-of-egress lighting and elevator controls, brings this building into compliance while still allowing historic elements (i.e., nonrated doors in the corridors) to remain. © International Code Council

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TABLE 1301.9 EVALUATION FORMULAS FORMULA

T1201.7

T1201.9

SCORE

PASS

FS - MFS > 0

39

(FS)



30

(MFS)



9



ME - MME ≥ 0

47

(FS)



40

(MFS)



7



GS - MGS ≥ 0

50

(FS)



40

(MFS)



10



a. FS = Fire Safety

FAIL

MFS = Mandatory Fire Safety

ME = Measure of Egress

MME = Mandatory Means of Egress

GS = General Safety

MGS = Mandatory General Safety

Figure 13.44 The solved equations in Table 1301.9 of the 2009 IEBC here show the difference between the total building scores, found at the bottom of the summary sheet in Figure 13.43, and the mandatory building scores, from Figure 13.41. Final scores of zero or greater indicate a passing score. Any values of NP (not permitted) that were scored on the Table 1301.7 summary sheet must be corrected regardless of the final passing scores seen here. © International Code Council

Based on this analysis, it would be permissible to do any amount of alterations or rehabilitation to the building if the described safety modifications are included. If the occupancy classification were changed, an analysis would have to be conducted for the new occupancy group. If the building were of mixed occupancy, then each occupancy would need to be separately evaluated based on its area, considering separations between occupancies.

The existing thirteen-story brick office building was reviewed and evaluated in its existing condition as it stands in the previous example. Now that same building will be evaluated with a number of improvements. For consistency and ease in following along, this example will retain the same numbering of safety element items that the IEBC and Table 1301.7 summary sheet use. Since work is suggested to improve the previous scores of the existing building, a new Table 1301.7 summary sheet will be developed that will reflect the condition of the building after all proposed safety work is done. This “improved building” summary sheet is seen in Figure 13.43.

EXAMPLE BUILDING

2

SCOPE: Existing High-rise with Required Improvements

Looking at the previously completed Table 1301.7 summary sheet for the existing thirteen-story office building seen in Figure 13.40, attention must first be given to the items that are not permitted no matter what building scores are achieved. These items must be updated, no matter what other work is done, so it makes a good starting place to see how the changes will improve the overall scores.

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Item 14. Elevator control—The previous Category b conditions (without Phase I and II recall) must be improved. To expect that the only elevator could be brought up to a Category d condition (complying with new construction requirements serving all occupied floors) might be overzealous, especially if the elevator is considered historic. The minimum improvement that would bring this item into an acceptable range would be to improve conditions to Category c—all elevators with Phase I and II recall as required by the International Fire Code. Doing so will bring the elevator control value up from NP to zero. Enter the zero in all three columns of the new summary sheet. Item 15. Means-of-egress emergency lighting—In the previous summary sheet, conditions fell into Category a—means of egress and exit signs not provided with emergency power in accordance with Section 2702 of the IBC. To bring the building conditions up to Category b—means of egress and exit signs provided with emergency power per IBC Section 2702, power must be provided for a duration of at least 90 minutes in the form of storage batteries, unit equipment, or an on-site generator, as noted in IBC Sections 1006.3 and 1011.5.3. The new value for the improved Category b conditions is zero; this is marked in the last two columns of the new Table 1301.7 summary sheet for this example. Additional improvements can also be proposed to raise the largest negative values, which gave the final score the hardest hits, and bring the building into compliance. Item 6. Vertical openings—Previously, it was stated that there was a nonrated open stairway that served all thirteen floors, a condition that carried a vertical openings value of -31. If the narrow, unornamented stairway was enclosed from the second to thirteenth stories with a 1-hour fire-rated stair enclosure, the remaining grand stairway between the first and second floor conforms to Section 707 of the IBC. In addition, if that 1-hour enclosure was extended to include protection of the elevator shaft and lobbies on the second through thirteenth floors, the vertical opening protection value (VO) could be reevaluated by letting Equation 13.5 reflect the new 1-hour enclosure: VO = PV × CF VO = 1× 1.2 VO = 1.2 ≈ 1 (Equation 13-5) Where: PV  (at least 1-hr rating)  1 CF  1.2 for Type I-A Construction

© International Code Council

Round this number to the nearest integer and enter +1 on the new summary sheet in all three columns. Item 13. Maximum exit access travel distance—Now that the stairway is enclosed in a 1-hour rated enclosure, the travel distance spiraling down the stairs does not have to be counted, so the unprotected travel distance is 123 feet. The new

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201

travel distance formula for this example, rounded to the nearest whole integer, looks like this: Maximum allowable travel distance − Maximum actual travel distance Maximum allowable travel distance 300 ft − 123 ft 0× Points = 20 300 ft Points = 20 ×

Points = 12

(Equation 13-5)

© International Code Council

Enter a +12 in the last two columns of the new summary sheet. With these noted improvements to the four items listed above, the final building score has improved dramatically but is still not enough to be considered compliant with the mandatory scores for a building of this B occupancy with Type I-A construction. Additional improvements must be proposed. Item 17. Automatic sprinklers—The previous Category a building had no sprinklers, or had sprinklers that were inadequate. If new automatic sprinklers were added throughout the building, as new work they will conform to Chapter 9 of the IBC, and as such will satisfy the requirements of Category e—sprinklers are required throughout; providing sprinklers throughout in accordance with Chapter 9 of the IBC will earn a value of +6 for this B occupancy in Table 1301.6.17. Enter +6 in the first and third columns of the new summary sheet. For the second column, divide the value by 2 and enter +3. Notice that the supposition of Category e, and not Category f, allows for the possibility that the existing nonrated corridor openings are to remain as is with the benefit of sprinklers. If Category f conditions can be shown, the score will only improve. Item 10. Smoke control—The addition of automatic sprinklers has a positive effect on the value for smoke control. Now the improved building can be called a Category b—building equipped throughout with an automatic sprinkler system. Compliant openings are provided in exterior walls in each story and distributed around the building perimeter in such a way to meet the Category b requirements. Table 1301.6.10 initially gives a score of +2 for this category, but downgrades the score to zero in Footnote a. Enter the score of zero in the last two columns of the summary sheet. Not only is this the next largest negative value in the summary sheet for the existing as-is building, it is an item that is often included with a new automatic sprinkler system, so it makes the logical next step. Item 9. Fire alarm system—Bringing the fire alarm system up to a Category e level might be too invasive to consider if it is not absolutely necessary. So, in keeping with the intent to see what the minimum amount of required work might be, it can be decided to bring this building up to a Category c level—smoke detectors in HVAC systems, installed in accordance with the requirements for new buildings in the International Mechanical Code. A fire alarm system of Category c has a value of zero in Table 1301.6.9. Enter this zero value in all three columns.

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Finally, this building has been evaluated with a number of proposed improvements that will bring it into conformity using the performance compliance method. The building with all of the improvements mentioned above is summarized in Figure 13.43. The final scores are evaluated in Figure 13.44 and shown to pass the compliance requirements of the performance compliance method. There is still one item that many owners might consider to improve the efficiency and desirability of lease space, and that item is the heating system. Item 7. HVAC systems—The existing radiators were originally scored with a benevolent value of +5 for the Category e system. However, if the heating system is modernized to one that includes ducts that serve multiple floors, the HVAC system will actually receive a lower value! Including the new HVAC system as part of the evaluation, knowing that it will reduce the final score minimally, shows what kind of impact the new heating and air conditioning system might have on the building’s safety. When providing a new HVAC system that is compliant with Section 1017.4 of the IBC and Section 602 of the IMC, use Category d to find the score of zero points, entered in all three columns of the new summary sheet. Item 8. Automatic fire detection—If a new HVAC system is installed, it could easily be installed with smoke detectors in the HVAC system to bring this item up to a Category c level. Table 1301.6.8 gives a score of zero for this condition in a B occupancy building. Without going into a long explanation for those items that were previously evaluated in the existing as-is building, the following safety parameters that are to remain unchanged are carried over: Item 1. Building height

10

Item 2. Building area

15

Item 3. Compartmentation (b) Item 4. Tenant and dwelling separation (c)

5 0

Item 5. Corridor walls (a)

5

Item 11. Means-of-egress capacity (a)

1

Item 12. Dead ends (b)

0

Item 16. Mixed occupancies (b)

0 6

Item 18. Standpipes (c) Item 19. Incidental use (n/a)

0

Totaling the Table 1301.7 summary sheet, seen in Figure 13.45, for the improved building with new HVAC, we find the following total values:

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Fire safety

38

Means of egress

46

General safety

49

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TABLE 1301.7 SUMMARY SHEET - BUILDING CODE Existing occupancy

B

Proposed occupancy

Year building was constructed

1920

Type of construction

I-A

B

Number of stories Area per Floor

Percentage of open perimeter increase

16.7

%

13

Height in feet

150

10,000 sq. ft.

Corridor wall rating

N/R doors

(full auto, sprinklers)

Completely suppressed:

Yes

X

No

Compartmentation:

Yes

X

No

X

Required door closers:

Fire-resistance rating of vertical opening enclosures Type of HVAC system

(H) HVAC

, serving number of floors

Yes

X

No

Type of location

Fire alarm system:

Yes

X

No

Type

Smoke control:

Yes

X

No

Type

Adequate exit routes:

Yes

X

No

Dead ends:

Maximum exit access travel distance

123' X

No

X

1-hr (lobby @ 1st floor)

Automatic fire detection:

Means-of-egress emergency lighting: Yes

Yes

In HVAC Per Sec. 907, IBC Auto. sprinklers, exterior windows

Elevator controls:

No

All

Mixed occupancies:

Yes

X (20')

No

Yes X (Phase I or II recall) No Yes

No

X

FIRE SAFETY (FS)

MEANS OF EGRESS (ME)

GENERAL SAFETY (GS)

1301.6.1 Building Height

10

10

10

1301.6.2 Building Area

15

15

15

SAFETY PARAMETERS

1301.6.3 Compartmentation

b)

5

5

5

1301.6.4 Tenant and Dwelling Unit Separations

c)

0

0

0

1301.6.5 Corridor Walls

a)

5

5

5

1301.6.6 Vertical Openings

1-hr

1

1

1

d)

0

0

0

1301.6.8 Automatic Fire Detection

c)

0

0

0

1301.6.9 Fire Alarm System

c)

0

0

0

1301.6.10 Smoke Control

b)

****

0

0

1301.6.11 Means of Egress

a)

****

1

1

1301.6.12 Dead Ends

b)

****

0

0

****

12

12

1301.6.7 HVAC Systems

1301.6.13 Maximum Exit Access Travel Distance 1301.6.14 Elevator Control

c)

****

0

0

1301.6.15 Means of Egress Emergency Lighting

b)

0

0

0

1301.6.16 Mixed Occupancies

0

****

0

1301.6.17 Automatic Sprinklers

e)

6

3

6

1301.6.18 Standpipes

c)

6

6

6

N/A

0

2  0

0

38

46

49

1301.6.19 Incidental Accessory Occupancy Building score - total value * * * * No applicable value to be inserted.

Figure 13.45 The completed Table 1301.7 summary sheet for the Building 2 example, with proposed improvements to the existing B occupancy office building to achieve passing final scores. The addition of a new HVAC system, stair enclosure, and automatic sprinklers, combined with the mandatory emergency power for means-of-egress lighting and elevator controls, brings this building into compliance while still allowing historic elements (i.e., nonrated doors in the corridors) to remain. © International Code Council

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International Existing Building Code Performance Compliance Method

TABLE 1301.9 EVALUATION FORMULAS FORMULA

T1201.7

T1201.9

SCORE

PASS

FS - MFS > 0

38

(FS)



30

(MFS)



8



ME - MME ≥ 0

46

(FS)



40

(MFS)



6



GS - MGS ≥ 0

49

(FS)



40

(MFS)



9



a. FS = Fire Safety

FAIL

MFS = Mandatory Fire Safety

ME = Measure of Egress

MME = Mandatory Means of Egress

GS = General Safety

MGS = Mandatory General Safety

Figure 13.46 The solved equations in Table 1301.9 of the 2009 IEBC show the findings and the differences between the total building scores, found at the bottom of the summary sheet in Figure 13.45, and the mandatory building scores, from Figure 13.41. Final scores of zero or greater indicate passing scores. The addition of the new HVAC system drops the final scores slightly, over those retaining the existing radiators, but the building is well within compliance with the passing scores shown. © International Code Council

Once again, the mandatory safety score for a Group B occupancy is subtracted from the building scores, with the resultant final scores shown here, as well as in Figure 13.46. Fire safety

38



(30)



8

Means of egress

46



(40)



6

General safety

49



(40)



9

With final scores that are zero or more, the building with the proposed improvements would be in compliance.

CONCLUSION The performance approach requires an understanding of the building and its safety systems. An in-depth investigation is needed, but when the requirements are determined, the design would be a straightforward process. This analysis would be applicable to future projects in this building. The performance compliance approach defines the bottom line for fire and life safety. There is also no one way to achieve a compliant retrofit. In the example above, we could have altered, or upgraded, features that would give a higher score and left other categories unchanged. This permits the designer to consider the proposed alterations in the context of identified deficiencies. Another use for the performance compliance approach is to evaluate a building that will really be altered using the prescriptive or work area compliance method. It would identify key areas of safety concern to be considered.

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CHAPTER

14

Summary of the Compliance Methodologies

In the previous chapters, example building rehabilitation projects were presented and the requirements of each of the three IEBC compliance methods were illustrated. The two buildings were a low-rise “Main Street” retail or office structure and a high-rise multistory office building. This chapter summarizes the findings and some of the issues identified.

LOW-RISE BUILDING The low-rise mercantile building was evaluated for 1. A simple project, tenant improvement, including new lighting, ceiling, floor covering, and painting. Both the original and the proposed occupancy were mercantile, Group M, so the project involved no change of occupancy character or group. 2. In a variation of this example, a project was considered that changed the building from mercantile to office use, from an M occupancy to a B. 3. A third example considered a change from mercantile to assembly by changing the space to a small dining facility. This is a change from an M to an A-2 occupancy. The findings are summarized in the table below.

205

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206

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Flexible provisions for historic structures if required and approved. Flexible provisions if required and approved.

Flexible provisions if required and approved. Alternate methods are permitted.

New work complies with IBC. Additional work triggered is difficult to anticipate. Change of occupancy— building must conform to IBC as if new. Extent of work undefined. Building official has authority not to mandate full compliance if the life and fire risk is less than the existing. Change of occupancy— building must conform to IBC as if new. Extent of work undefined. In this case there may not be a reduction in fire and life risk requiring review of alternative approaches if there are conflicts.

Example: M to B occupancy

Example: M to A-2 occupancy

HISTORIC

PRESCRIPTIVE

Follow step-bystep in IEBC. There may be triggers due to increased risk due to the A-2 occupancy.

Egress capacity must be reviewed. IEBC requires step-by-step list in Sections 903 through 912. This building should not pose any special problems.

New work complies with IBC. Defined area limits trigger minimum additional work.

Chapter 11 may be an approach if there are conflicts. This would entail considering and documenting alternatives.

If issues arise, Chapter 11 may be an approach. This would entail considering and documenting alternatives.

No unique conditions.

HISTORIC

WORK AREA

COMPLIANCE METHODS

Example: M to M occupancy

LOW-RISE EXAMPLE BUILDING

Must analyze entire building. Scoring system allows giveand-take to achieve conformity. Allows flexibility to achieve conformance, especially when increasing risk with occupancy change.

Must analyze entire building. Scoring system allows give-and-take to achieve conformity. Cumbersome for occupancy change to lower risk.

Must analyze entire building for the safety measures. Exit signage and lighting may be required

No criteria for historic alternatives.

No criteria for historic alternatives.

No criteria for historic alternatives.

HISTORIC

PERFORMANCE

Scope of work is the same in all three examples—an interior renovation including paint, flooring, ceiling, and new lights. The doors and storefront remain unchanged. Toilet room remains unchanged. For simplicity, it will be considered acceptable as it stands today.

IEBC COMPLIANCE METHOD COMPARISONS

207

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Alteration Level 2. New work complies w/IBC. Triggered work may include the enclosure of the stair at the floor of work. The enclosure requirements are less rigorous (1-hr enclosure, not 2-hr per IBC).

The wainscot paneling in the corridor could be an issue and require special consideration.

Will require discussion on corridor doors and walls and the effect on them.

New work complies with IBC. Additional work triggered is hard to anticipate. Triggered work may exceed intended work area by additional corridor requirements.

New work complies with IBC. Additional work triggered is hard to anticipate. Extent of stair enclosure may exceed level of work area.

Scope: interior TI + corridor door on 6th floor

Scope: complete remodeling of 6th floor

New work complies w/IBC. Follow step-bystep in IEBC. Stairway enclosure must extend from the work area floor to the floor of exit.

Alteration Level 1. New work complies with IBC, defined area limits triggered work.

New work complies with IBC. Additional work triggered is difficult to anticipate.

Allows retention of historic items.

Allows retention of historic items.

IEBC Chapter 11 may offer alternative approaches.

HISTORIC

WORK AREA

COMPLIANCE METHODS

Scope: interior tenant improvement on one floor

HISTORIC

PRESCRIPTIVE

HIGH-RISE EXAMPLE BUILDING

Scope of work differs in all three high-rise examples.

IEBC COMPLIANCE METHOD COMPARISONS

Gives quantifiable value to safety of building.

Must analyze entire bldg. Scoring system allows give-and-take to achieve conformity. Allows flexibility to achieve conformance by correcting various deficiencies.

Must analyze entire building. Scoring system allows give-and-take to achieve conformity.

Must analyze entire building, expanding scope beyond intended. Gives very specific evaluation. Allows lessthan-new for some items. Gives quantifiable value to safety of bldg.

Allows retention of historic items per above.

Allows retention of historic items per above.

No special exceptions for historic buildings. The alternate materials and methods provisions would be used if there is a significant issue with historic fabric.

HISTORIC

PERFORMANCE

208

Summary of the Compliance Methodologies

HIGH-RISE BUILDING The three examples of the high-rise building are summarized below. They are evaluated for 1. A tenant improvement project involving new lighting, floor covering, and ceiling with no reconfiguration of space. 2. A larger tenant alteration that may involve the addition of a door into a corridor as well as some minor reconfiguration of the interior space. 3. A tenant alteration that may exceed 50 percent of the floor area.

SUMMARY In the example buildings, no one method was appropriate for all types of alteration and change of occupancy projects. One or the other may be simpler to implement. Each may trigger unanticipated requirements. The prescriptive approach is the simplest for the smaller projects but may have additional requirements that cannot be anticipated. The work area method, for the most part, is predictable, but improvements may be required beyond the owner’s defined work area to provide additional safety in the building. The performance compliance approach provides a good understanding of the fire safety issues with a building, whether the project is proposed as an alteration or as a change of occupancy.

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PART

5

HISTORIC PRESERVATION REGULATIONS

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CHAPTER

15

The Legal Basis for Historic Preservation Regulations

FEDERAL LEVEL American Antiquities Act of 1906 Although historic preservation was a concern in the United States during the nineteenth century, efforts were almost entirely focused on specific landmarks and were carried out by volunteers associated with those structures. The first national legislation to promote protection of historic resources was the American Antiquities Act of 1906. Though this act was national in scope, it continued the emphasis on individual landmarks, which were designated by presidential proclamation.

Historic Sites Act of 1935 The National Park Service was established in 1916, but preservation of historic structures was not one of its primary responsibilities. That role would not become prominent until the Historic Sites Act of 1935. In addition to being the first official pronouncement of historic preservation as national policy, the Historic Sites Act established several important vehicles for preservation. One was the Historic American Building Survey (HABS), which combined written description, photographs, and measured drawings to document historic structures across the United States. The intent was as much a Depression-era makework program as anything else, but it began a slow transformation of the focus on major landmarks. HABS—possibly because it did have an objective of keeping people employed—documented minor structures as well as major ones, and established a record of historic structures that would be a significant contributor to the historic preservation movement for many decades. The Historic Sites Act also placed administration of historic preservation matters in the jurisdiction of the National Park Service and established the predecessor of the National Register of Historic Places. Association with historically 211

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significant events or people may confer singularity on structures that are not physically distinguished. Structures may be important in themselves or as part of a neighborhood or district.

National Historic Preservation Act of 1966 In 1963, in spite of heated protests, Pennsylvania Station in New York was torn down to make way for more profitable use of its site. Architecture critic Lewis Mumford called its destruction “an irresponsible act of public vandalism.” The loss of this building is commonly regarded as the major impetus for the National Historic Preservation Act of 1966. The Act increases the ability of the federal government to delay or require modifications to proposed work on designated historic buildings.

National Environmental Policy Act of 1969 The National Environmental Policy Act of 1969 reiterated that preservation of historic resources is national policy. Historic preservation is regulated in the United States by the National Historic Preservation Act of 1966, Executive Order 11593, and the Secretary of the Interior’s Standards for Treatment of Historic Properties (1976). Under these regulations, the community—including posterity as well as the community of the present—acquires partial rights in privately owned buildings based on architectural or historical singularity. Architectural singularity may derive from unique design, design highly characteristic of a particular style, superior workmanship, irreplaceable materials, or other physical characteristics.

Executive Order 11593 of 1971 Executive Order 11593, issued in 1971, directed federal agencies to take the lead in preserving, restoring, and maintaining properties that are under their control. It also required that such properties be inventoried and documented.

The Secretary of the Interior s Standards of 1978 The Secretary of the Interior’s Standards for Treatment of Historic Properties, originally published in 1978 as The Secretary of the Interior’s Standards for Historic Preservation Projects, served as the required technical basis for federal grants, tax credits, and community development block grants. The Standards divide approaches to historic structures into four categories: preservation, rehabilitation, restoration, and reconstruction. Selection of category is based on a structure’s importance as well as its condition. All categories are well explained, and guidelines provide concrete examples. Each of the four approaches is most appropriate under particular circumstances, and the designer’s first task is to decide which approach to follow. The choice of approach must be a natural outgrowth of the reasons why the building is

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important. Because the Standards are such an important tool in preservation policy and practice in the United States, Chapters 17 will examine them and the guidelines that are used in their implementation. Guidelines for Implementing the Standards The Standards are supplemented by guidelines that provide detail about how the Standards should be implemented. These guidelines are not tightly prescriptive. Instead, they offer preferred alternatives, based on the approach that identification, preservation, and repair of historic materials are the rule, rather than the exception, in work on historic buildings. Accordingly, the guidelines emphasize that, in addition to considering elements on a case-by-case basis, the cumulative effect of all decisions be considered in a planned way. The guidelines also reinforce provisions of the Standards that forbid the use of conjectural details, emphasizing that an element cannot be returned to function in the historic palette unless it has been thoroughly documented prior to its loss. The body of the guidelines is a series of chapters concerning various materials, such as wood and masonry; building elements, such as roofs and storefronts; systems; site issues; code-related considerations, such as accessibility and energy; and other topics, such as additions. In each case, a specific and detailed description of recommended and nonrecommended actions gives guidance in solving some of the more common problems associated with that topic. In addition to federal regulations, many states have regulations, environmental regulations, and, as described earlier in this book, building code provisions for historic buildings. With fifty states plus the territories, it is almost impossible to identify and list them all. Discussed below are laws and regulations to look for in a community with a proposed preservation project.

STATE LAWS AND REGULATIONS Many states have historic preservation regulations. Included are State registers—Many states have registers of historic places. In many cases, these registers list buildings and sites that may not be eligible for the National Register but are considered important within the state. In other cases, the state register may include sites where there is no longer a structure, only a marker that a historic event took place there. State historic building codes—Some states have adopted specific codes for historic buildings. These were discussed earlier based on the report in 1976 by the National Bureau of Standards (now the National Institute of Standards and Technology). More have adopted provisions since that survey. These regulations may differ from those in the IEBC and may be more or less restrictive than the IEBC. State environmental laws—State environmental regulations may require compliance with the Secretary of the Interior’s Standards for the Treatment

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of Historic Properties. These regulations usually reference the Secretary of the Interior’s Standards as the compliance requirement. The environmental regulations may trigger archaeology studies for preservation projects and may limit some choices for building rehabilitation. Tax laws—Some states have tax incentives for historic preservation projects. These may include tax credits and property tax write-downs or reductions.

MODEL CODE PROVISIONS As described in Chapter 3 of this book, model code provisions gradually have become more detailed and more sophisticated in their application to historic and other existing buildings. Of particular importance in the International Existing Building Code is Chapter 11, which sets the ground rules for application of the code to historic structures.

LOCAL LAWS Many cities have conducted surveys of historic resources and neighborhoods. Some also designate local historic landmarks. Often, such structures are not eligible for the National Register or state historic registers. Local historic districts, such as Historic Preservation Overlay Zones (HPOZ), contain numerous buildings that are not individually listed but probably are eligible to use the historic building code provisions. Since a building must be listed in a register of historic structures for the IEBC and other building codes to be used, a local listing should make the structure eligible. Local registers may be less well known than other listings, so it is important to be aware of them as a possibility when considering use of the IEBC.

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CHAPTER

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The Rationale Behind Historic Preservation Regulations

UNDERLYING PHILOSOPHY OF THE STANDARDS At first glance, the Secretary of the Interior’s Standards is a highly intellectual and apparently academic set of rules. It may proscribe work that owners would very much like to do, for reasons they may find hard to understand. And, although following the standards is generally not mandatory, violating them will close off most grants and other funding sources, other than the owner’s private resources. For this reason, opposition to the Standards is common. This attitude reflects a misunderstanding of the reasoning behind the regulations. The philosophy of historic preservation that underlies the Secretary of the Interior’s Standards has been evolving worldwide for over a century. Without an awareness of this philosophy, the Standards may appear arbitrary. And unless the bases for the Standards are spelled out, misunderstandings about objectives may arise between preservation professionals, their clients, and regulatory personnel.

ACCURACY VERSUS SUBJECTIVITY One of the most important of these principles is that the past must be represented accurately rather than subjectively. Stated simply, this means that the treatment of a building must reflect what was actually constructed in that building, either originally or at some point in the building’s history. No project—regardless of the treatment approach selected—should be based on guesses, even if those conjectures are limited to features and materials typical of the building’s period. This is the principle behind provisions in the Guidelines for Rehabilitation, Restoration, and Reconstruction that forbid creating “a false sense of history by adding conjectural features, features from other properties, or by combining features that never existed together historically.” This provision draws a sharp line between historic preservation design and an art that often seems to be confused with it: the art of designing stage settings. In 215

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literature, maintaining a similar distinction between fact and fiction is properly seen as an ethical matter. The distinction between accuracy and subjectivity can be understood as an ethical divide in historic preservation as well. The reasons for this restriction go back to the earliest days of organized building restoration, and to many instances of interpretive and romanticized “restoration” that were later bitterly regretted for their inaccuracy and for the destruction of real historic fabric that accompanied them. Thus, an insistence on truthfulness in the treatment of historic buildings has become a tag for identifying skilled design professionals. However, it would be a mistake to interpret the Secretary of the Interior’s Standards to mandate museum-quality restoration as opposed to any other preservation approach. The Standards accept use of new materials and equipment in buildings as long as those additions make no claim to historical authenticity. There are several ways to implement this “nonfiction” approach to design. Obviously, if a building has been completely documented, it would be possible to restore it to the recorded condition. If that approach were judged to be desirable, each changed element could be replaced with a facsimile of a documented element. If the facsimiles were dated and properly documented, this would be an acceptable approach to historic preservation. In fact, this is what is correctly meant by the word “restoration.” If documentation is incomplete or nonexistent, true restoration is impossible. In this case, a rehabilitation approach would be appropriate. In rehabilitation, it is recognized that the design incorporates both old and new elements. The accuracy principle is served by avoiding the use of elements that seem to be authentic, but are not. New elements are usually intended to be secondary, to yield center stage to historic fabric. For example, in rehabilitation of a nineteenth-century building that retains its ornate crown moldings and door casings but not its original wood base, new base moldings might be chosen to blend unobtrusively, allowing original work to claim the viewer’s attention. A modern rendition of Victorian woodwork would not be used, nor would an accurate reproduction of a molding used in another building. Another acceptable use of new elements is in provision of safety and livability. In this case, buildings may be modified to incorporate seismic safety improvements or modern amenities such as bathrooms. As much as possible, such alterations would be carried out without destruction of significant historic materials. Recording changes, documenting any removals, and interpretation of added materials help to keep work of this kind from being mistaken for historic fabric. New elements would be simple and understated, not faux-antique. For example, in providing a new kitchen or bathroom in a historic building where these facilities were nonexistent or undocumented, it would be desirable to provide ordinary appliances, cabinets, and counters rather than try for an antique appearance that will necessarily be mendacious—either because it is inaccurate or because it is accurate for another building or another period.

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REPRODUCTION VERSUS ORIGINAL The Standards reiterate at every level that no reproduction is equivalent to original historic fabric. At building scale, the Standards include criteria for reconstruction of structures. According to the discussion of this approach in the Standards, Much like restoration, the goal is to make the building appear as it did at a particular—and most significant—time in its history. The difference is, in Reconstruction, there is far less extant historic material prior to treatment and, in some cases, nothing visible. Because of the potential for historical error in the absence of sound physical evidence, this treatment can be justified only rarely and, thus, is the least frequently undertaken. Documentation requirements prior to and following work are very stringent. Measures should be taken to preserve extant historic surface and subsurface material. Finally, the reconstructed building must be clearly identified as a contemporary re-creation.

At smaller scales, reproduction of well-documented building features may be appropriate. However, the original feature must be sufficiently documented to show that the reproduction is not conjectural. At the scale of building elements, repair is preferred over re-creation of deteriorated materials, even if the repair is less than perfect. Worn authentic elements are strongly preferred over new facsimiles, unless reduced performance of the repaired element affects safety. If it is necessary to replace individual elements, it is good practice to sign and date them in a place that is not visible to casual inspection—for instance, on the back of a wall panel. This at least clearly distinguishes the replaced element from similar historic ones if the building is carefully examined or rehabilitated again in the future.

REVERSIBILITY Changes that cannot be undone without damage to the original building must be considered more stringently than those that may easily be undone. This is the principle of reversibility, and it applies at several levels. Most obvious, permanent removal of historic features is irreversible. In cases where removal is necessary, the materials must be documented photographically and by measured drawings prior to any work. At smaller levels, reversibility must be considered for materials. For example, it is relatively easy to patch plaster to hide nail or screw holes, but similar patching of wood members is very difficult. Work may be irreversible at a molecular level. An example would be application of chemical treatments, cleaners, or sealers that permanently change the properties of the surfaces contacted. A treatment should have a considerable history of problem-free use on nonhistoric structures before it is considered for use in preservation projects.

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The principle of reversibility also applies to earthwork in historic areas and to excavation of archaeological resources. Because it is not possible to put the soil back in its undisturbed state, all earthwork is irreversible, and must be approached with particular caution. All work should be considered in terms of reversibility at every level.

CONTINUITY OF HISTORY A building’s history does not stop the day the building is completed. In a few cases, some event of overriding importance may justify “freezing” a building’s development at a particular date. In such cases, a restoration treatment would be selected, supposing adequate documentation to be available. Far more commonly, buildings—even very important buildings—have historical significance over a period, or over the entire course of their existence. In these cases, the appropriate treatment for the building would be to preserve all its fabric, including alterations over time, documenting and interpreting as necessary to make the building’s history accessible. Removing alterations that have historic significance in their own right is not permitted by the Standards.

EXAMPLES Historic Church A church has been severely damaged by fire. The congregation and building committee are not in agreement about how to proceed. Before the fire, sporadic interest in “restoring” the building had been found to be impractical because of expense. Several ideas for modernization of the basement have been brought up by the congregation. The church’s basement, originally used for storage, has been pressed into use as meeting rooms within the past decade. It lacks kitchen and bathroom facilities and is otherwise less than ideal for the new use. However, the building committee questions whether such work can be done, because it is not original to the historic building. Because of the fire, historic preservation grants may be available, but almost all of them require adherence to the Secretary of the Interior’s Standards. The original pews have been removed, but a few of them still exist in the church’s social hall. The pews in place at the time of the fire were destroyed. One of the stained glass windows was destroyed. Wall finishes in the area around the altar were damaged by smoke. The roof was slate, and had been maintained well enough to be watertight. However, that maintenance had grown more expensive over the years, and the building committee would like to replace the roof, even though it was not damaged in the fire. The church as constructed had no handicapped access. What should be provided now? Though the exterior is relatively undamaged, the building department expects a reasonable degree of compliance with current standards.

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The building is a community landmark, but has no special events or notable individuals associated with it. No complete record of the building at any time is available. Available records include Drawings—The building was constructed in 1840 and no architect’s drawings exist currently, if they ever did. Drawings of an electrical remodeling in 1995 do not show anything but the building’s overall shape and proposed changes to the electrical system. Paintings—A few undated amateur paintings of the building’s exterior are available, but the skill of the artists is unknown, and the paintings contradict one another in a few important areas. All but one show the church as a reddish color. Photographs—The earliest exterior photographs of the building are undated, but based on clothing of people in the photographs, probably were taken around 1900. Other exterior photographs exist, some similarly datable from clothing and car styles, or based on long-time members’ memories of when certain landscaping features existed. One church member has an interior photograph he says was taken in 1840, immediately following construction. This photograph shows a corner of what appears to be a flat, beamed ceiling. The earliest datable interior photographs show a wedding that took place in 1931 and are focused on the bride and groom. They do include a few details of the church interior. Other interior photos exist, some datable, others not. Most are from recent years. One shows the destroyed stained glass window clearly. Both interior and exterior photos show that the building has changed over the years. Other documents—Church records mostly deal with baptisms, marriages, and burials. Only a few records of the building exist. One is a tradesman’s bill for construction of an ornate ceiling in 1880. No drawings or other records of that ceiling exist. Some of that construction was removed around 1920; the rest remained until the fire. Another record is a personal letter in the files of the historical society. It is dated 1890 and describes the church exterior as stone. All photographs show a brick exterior, but one of the paintings is a color that suggests a stone façade. Analysis

Treatment Approach No detailed plans or photographs show the entire church at any specific point in time. The lack of complete documents makes the restoration approach impossible. Lack of a specific historical association or special period of significance would make selection of a target date very difficult even if better documentation did exist. The appropriate choice would be rehabilitation.

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Documentation Some of the documentation is questionable. The date of 1840 ascribed to the photograph of the flat, beamed ceiling is almost certainly inaccurate. Photography was in its infancy in 1840, and a casual photograph of a building interior is all but impossible to believe. A photograph of a small segment of a building is also questionable, unless it shows details that definitely are associated with the building. Otherwise, it may be a photo of another building altogether. Snapshots taken in the church can give a little information, but the building is not their focus, and they are almost never sufficient for restoration of specific features. Likewise, paintings are not good evidence of the building’s appearance unless a great deal is known about the competence of the artist. Amateur artists’ depictions may be interesting, but they are not verifiable records of a building’s original colors or even of its shape. Building records are reliable, but in this case, the only such records are a sketch plan and a bill for the ceiling. Neither gives enough detail to provide documentation for restoration of any feature. A personal letter, though of historical interest, suffers from the same lack of verifiable expertise as amateur paintings. It is possible that a writer would describe a brick building as “stone,” and unless solid evidence that it did at one time have a stone façade emerges, the letter is only a curiosity. Recommendations Since the project is a rehabilitation, modernization of the basement is appropriate, provided funds can be found to accomplish it. However, upgrading the basement is secondary in importance to correcting the fire damage, and may not be eligible work under the terms of some grants. The main part of the church is a more difficult decision. There is no complete record of its details at any time other than that immediately preceding the fire. Restoration of a few elements is possible, and should be considered carefully. The ceiling should be repaired and refinished to eliminate smoke damage, but the lack of any credible record of its previous appearance makes it impossible to alter it. Restoration of the ruined window is possible because good documentation of this feature exists. This kind of small, artistic, and very visible project is a good one for the church to fund with special donations or grants. Restoration of finishes in the altar area is also possible. Finishes should be examined by a conservator to see what underlies the wood and painted plaster that existed immediately before the fire. It is possible that historic finishes will be found, and the congregation and building committee will have to decide whether to restore them. This is also a project that could be funded with special donations or grants. Duplication of the original pews is also possible, since a few still exist. It would be an attractive project for special funding. The congregation and building committee should consider such a project carefully, however. Pews built in 1840 may be very uncomfortable for the taller people of the twenty-first century. It may be more

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practical to purchase unobtrusive modern pews. The existing historic ones should continue to be preserved. The undamaged slate roof should not be replaced. To do so would be a violation of the Secretary of the Interior’s Standards, and would endanger funding for the remainder of the project. Handicapped access is important, and the church’s architect should explore ways to incorporate it unobtrusively as part of the project. Early conferences with appropriate code enforcement personnel should establish acceptable solutions for access.

Victorian House A fine example of the Queen Anne style, the house was constructed in 1892. It has two stories, with a tower and numerous porches, dormers, and gables. It also has a full basement. The upper stories are wood frame. The basement walls are brick. The house is on a large corner lot in a historic city neighborhood near a major university. The neighborhood is mixed use, including apartments, single-family dwellings, and small businesses. The house was used as a private residence until World War II, when it became a boarding house. Converted to apartments after the war, it retains many of its original details, although some have been damaged by new partitions or covered by new finishes. The 10-foot ceilings on the lower floor were replaced within the living units with suspended acoustical panels. Investigation behind these panels reveals that the original plaster ceilings, moldings, and rosettes are all in place, though some are water-damaged. Corner fireplaces in two rooms on each floor share a chimney. The original stairway remains, but its rise and run are not in conformance with current code. Original doors and windows remain. The windows are not in conformance with current energy standards, and the new owners wonder if they should be replaced. The original roof was wood shingles. The current roof is composition shingles, fairly new. A firm of lawyers wants to use the building for offices and would like to restore its detail as accurately as is practical. They would like to append a small, one-story addition at the rear for use as a computer center and a handicapped toilet room, to install a new HVAC system, and to remove asbestos siding from the exterior. In addition, they want to restore interior finishes and remove the suspended ceiling. They would like to find appropriate lighting fixtures for the major rooms. They plan to repaint the building in eye-catching “painted lady” colors. The house is in a seismic area and has had no structural upgrading. The foundation is brick, mostly in good condition, but with two isolated areas of mortar loss. The house was built from one of the Victorian pattern books, so approximately accurate original drawings exist. Several exterior photographs show the building’s two principal elevations prior to World War II. No interior photographs have been found.

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Analysis

Treatment Approach The lawyers will not be using grant money or tax incentives to fund the project. However, they want to treat the building in accordance with the Secretary of the Interior’s Standards. Because this project entails a change of occupancy and an addition, it is a rehabilitation project. Documentation Written records are nonexistent, and photographs are sparse. However, the building contains considerable evidence of what was in place before its adaptation as a boarding house. Recommendations Insofar as possible, available documentation should be followed in the rehabilitation. Partitions added to divide the building into apartments should be removed, and the floor plan returned to its original configuration. The addition is the major alteration, and it should be constructed where it is least conspicuous. The details of the addition should not imitate those of the original building, nor should they set up a strongly contrasting aesthetic. Instead, the addition should be constructed to be subordinate to the house. To the greatest extent possible, the addition should be constructed in such a manner that, if it were removed, the original house would be intact. The original windows should be repaired rather than replaced. If any are too deteriorated for repair, they should be duplicated, preferably with a concealed notation concerning their date. The intact roof does not need to be replaced. However, when re-roofing is needed, the lawyers should consider wood shingles if they are permitted by current code. In deciding on exterior paint colors, the lawyers should evaluate how the building fits into the neighborhood. If “painted lady” colors would detract from the historic district, they should consider something more in keeping with the overall environment. The suspended ceiling should be removed, and the ceilings restored, supposing that enough of the original fabric is in place that such a restoration would be accurate. It should be noted here that in a rehabilitation project, accurate restoration of individual features is appropriate. Similarly, if paint seriation reveals earlier or original colors and finishes that are appropriate for the law office, such items might be seriously considered, but use of original finishes would not be mandatory, since the project is a rehabilitation.

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CHAPTER

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The IEBC and the Secretary of the Interior s Standards

Prompted by the loss of Penn Station in 1963, the National Historic Preservation Act of 1966, and its implementary offshoots, Executive Order 11593, The Secretary of the Interior’s Standards and Guidelines, addressed the imbalance between economic and cultural forces that existed at that time. These efforts were supplemented with tax credits, block grants, and other incentives to preserve historic structures and neighborhoods. The Secretary of the Interior’s Standards for Treatment of Historic Properties provides a choice of four treatment approaches. Each is appropriate for particular situations, depending on the building’s importance, its projected use, how much of the historic fabric remains, and the amount and quality of documentary evidence of its history. The four treatment approaches are preservation, rehabilitation, restoration, and reconstruction. The Standards are accompanied by Guidelines to help decide which treatment is appropriate and how to implement it. Both the Standards and the Guidelines are available in print and online. The overall objective of the Standards is to map procedures for maintaining integrity in work on historic structures and for avoiding preventable loss of historically important materials and features. The chosen approach must always reflect and fulfill the reasons behind the building’s importance. If a building’s significance is diffuse, based on its role in a community over an extended period of time rather than association with any outstanding event, person, or architectural style, the project would most appropriately consider the preservation or rehabilitation approaches. The former would be most appropriate for buildings that have little damage or deterioration, particularly ones for which a major change of use is not necessary. The latter would best be used if many elements are damaged or missing, important information about layout and materials is not known, or a major change in use is necessary for the building’s continued survival. The vast majority of projects involving historic buildings use the rehabilitation treatment approach. 223

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Restoration and reconstruction are appropriate for buildings that have a sharply focused significance: a historical event, an association with an important person, a design by a well-known architect, an embodiment of an architectural style—all of these would be reasons for saving a building. Such reasons would suggest that significance is intertwined with a particular moment in time. If the building is extant, restoration to that moment of focus is appropriate; if it is not, reconstruction to its appearance at that moment would be the desirable course. Restored and reconstructed buildings are most often used as house museums or for similar functions where appearance and authenticity can transcend most practical considerations.

PRESERVATION Background and Definitions Preservation is defined by the Standards as “the act or process of applying measures necessary to sustain the existing form, integrity, and materials of an historic property,” and includes maintenance, repair, and code-required improvements to electrical, mechanical, and other systems. According to the Introduction: The first treatment, Preservation, places a high premium on the retention of all historic fabric through conservation, maintenance and repair. It reflects a building’s continuum over time, through successive occupancies, and the respectful changes and alterations that are made.

“Retention of all historic fabric” is a concept that has been subjected to a variety of interpretations. Some have narrowed the word historic to mean only fabric that existed during a selected period of significance; others have broadened it to include all fabric, not excluding recent graffiti. Most professionals would not be likely to include damage and deterioration as items to be preserved, since maintenance and repair are acceptable work under this approach.

Secretary of the Interior’s Standards for Preservation 1. A property will be used as it was historically, or be given a new use that maximizes the retention of distinctive materials, features, spaces, and spatial relationships. Where a treatment and use have not been identified, a property will be protected and, if necessary, stabilized until additional work may be undertaken. 2. The historic character of a property will be retained and preserved. The replacement of intact or repairable historic materials or alteration of features, spaces, and spatial relationships that characterize a property will be avoided. 3. Each property will be recognized as a physical record of its time, place, and use. Work needed to stabilize, consolidate, and conserve existing historic materials and features will be physically and visually compatible, identifiable upon close inspection, and properly documented for future research.

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4. Changes to a property that have acquired historic significance in their own right will be retained and preserved. 5. Distinctive materials, features, finishes, and construction techniques or examples of craftsmanship that characterize a property will be preserved. 6. The existing condition of historic features will be evaluated to determine the appropriate level of intervention needed. Where the severity of deterioration requires repair or limited replacement of a distinctive feature, the new material will match the old in composition, design, color, and texture. 7. Chemical or physical treatments, if appropriate, will be undertaken using the gentlest means possible. Treatments that cause damage to historic materials will not be used. 8. Archeological resources will be protected and preserved in place. If such resources must be disturbed, mitigation measures will be undertaken.

Application to Specific Projects If a building’s importance is based on its use over time, preservation is likely to be the appropriate approach. Such a building might be of only local significance, and it may have changed and evolved over the years. It may have elements of several architectural styles or periods. It would probably have no special relationship to major historical events or distinguished personages. This is likely to be the best approach where no formal documentation of the building exists. Preservation is ideally suited to a building where a consistent thread unifies the building’s elements. Ancillary fabric and contents might be included in the preservation effort. Examples might include 

The home of several generations of a locally interesting or important family.



A still-functioning neighborhood church, for generations the site of local weddings, baptisms, and funerals, but associated with no events of great significance.

At times, local sentiment may come down heavily in favor of “restoring” such a building to an original, or other former, state. Since the reason for saving such buildings is respect for the continuum they represent, removal of part of this continuum would be a serious error and, in fact, a violation of the Secretary of the Interior’s Standards. Many, if not most, changes made by successive generations would correctly be considered historic fabric. Preservation is usually best suited to buildings that are in fairly good condition to begin with. If many building elements are damaged or deteriorated, it may be impossible to know how they looked when intact. Preservation requires accurate knowledge concerning the items being preserved and in the face of uncertainty becomes less and less feasible. As a rule, repairs must be carried out with materials identical to those of the original building, and they must also perfectly duplicate any replaced elements. But they also must be identified as belonging to their own time. This may be done unobtrusively by marking elements in a way that would be hidden to casual view.

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Preservation does not apply to proposed additions or new construction, only to extant fabric at the time of a project’s inception. It does allow for code-required work, but it would be good practice to install anything of this nature in such a way that it could be removed without significant effect on the historic fabric.

Preservation and Building Code Provisions Given that the definition of preservation involves replacing as little material as possible and using materials identical to existing materials, the best choice of code approach under the IEBC would probably be either the repair provisions of Chapter 11 of the IEBC or the work area method, repair option.

REHABILITATION Background and Definitions The Introduction to the Standards defines rehabilitation as the act or process of making possible a compatible use for a property through repair, alterations, and additions while preserving those portions or features which convey its historical, cultural, or architectural values.

Like preservation, rehabilitation is an approach best adapted to a structure that has a continuum of use over a long period rather than a precise moment of historical importance. However, returning to the desirability of a good fit between the approach to the work and the reasons why the building is significant, the following characteristics would make rehabilitation the approach of choice: 

Widespread deterioration, to the point where preservation or restoration would be based on conjecture rather than on extant materials.



A need for significant alterations or additions for continued functioning.



A structure that contributes to a historic district but has a low degree of individual significance.

The Secretary of the Interior’s Standards for Rehabilitation 1. A property will be used as it was historically or be given a new use that requires minimal change to its distinctive materials, features, spaces, and spatial relationships. 2. The historic character of a property will be retained and preserved. The removal of distinctive materials or alteration of features, spaces, and spatial relationships that characterize a property will be avoided. 3. Each property will be recognized as a physical record of its time, place, and use. Changes that create a false sense of historical development, such as adding conjectural features or elements from other historic properties, will not be undertaken.

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4. Changes to a property that have acquired historic significance in their own right will be retained and preserved. 5. Distinctive materials, features, finishes, and construction techniques or examples of craftsmanship that characterize a property will be preserved. 6. Deteriorated historic features will be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature will match the old in design, color, texture, and, where possible, materials. Replacement of missing features will be substantiated by documentary and physical evidence. 7. Chemical or physical treatments, if appropriate, will be undertaken using the gentlest means possible. Treatments that cause damage to historic materials will not be used. 8. Archeological resources will be protected and preserved in place. If such resources must be disturbed, mitigation measures will be undertaken. 9. New additions, exterior alterations, or related new construction will not destroy historic materials, features, and spatial relationships that characterize the property. The new work shall be differentiated from the old and will be compatible with the historic materials, features, size, scale and proportion, and massing to protect the integrity of the property and its environment. 10. New additions and adjacent or related new construction will be undertaken in such a manner that, if removed in the future, the essential form and integrity of the historic property and its environment would be unimpaired.

Application to Specific Projects Rehabilitation is probably the most commonly chosen approach because it applies best to buildings of architectural interest but with no unique place in history. Rehabilitation may also be the approach that best incorporates the economic reality that not all buildings, indeed, probably not even all important buildings, can be used for their original purpose or function as museums. Neighborhoods change, uses change—and if the buildings are not able to change as well, many of them may be lost. Rehabilitation seeks to preserve the best of the historic fabric, while detaching from the need to represent the building as an intact survival from the past. Examples of buildings for which rehabilitation would be appropriate would be 

A large, deteriorated single-family dwelling that is to be repaired and altered for use as offices.



Downtown industrial or office buildings for which the current economic use is residential lofts.



A disused school building that can fill a need for a new community center.

In each case, the building may have no economic future, unless it can be adapted for a new use, often with considerable loss of historic fabric. The professional’s task is to identify which architectural elements may reasonably be sacrificed, and which must remain. Incorporating the essential elements into efficient service in

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the new use is one of the major tasks of rehabilitation design. It is a necessity if the requirements of the Secretary of the Interior’s Standards are to be met.

Rehabilitation and Building Code Provisions Rehabilitation of a historic building has more in common with ordinary remodeling of existing buildings than is the case with any of the other approaches that are defined by the Secretary of the Interior’s Standards. This has the possibility to be both an advantage and a drawback. It may work to the benefit of a project, because the approach allows greater flexibility so that closer adherence to the code is possible without violating the Standard. However, buildings for which this approach is best used are probably perceived as lesser in value than the community landmarks for which preservation or restoration would be appropriate. Thus, regulatory officials may be less inclined to accept alternatives than would be the case with more prominent buildings. Any of the three approaches—prescriptive, work area, or performance—will work for a rehabilitation project. Choice of approach depends partly on the extent of work and partly on the individuals who will be involved with the process. Prescriptive Compliance Method 

In the prescriptive approach, the building and fire department representatives take a primary role. Consider the prescriptive approach if these individuals have considerable experience with historic structures.



If possible, avoid the prescriptive approach if code officials are inexperienced with or unsympathetic to historic preservation.



For large projects, the prescriptive approach will require numerous meetings to resolve code issues. Such meetings must be staffed by upper-level people from both the design office and code enforcement bodies. Consider whether the project budget will support a preliminary design phase of this magnitude and whether the local building and fire departments have the interest or the time to participate.



Preparation for such meetings will involve considerable research and preparation on the part of the design office. Much of the potential for success of project meetings will depend on this preparation.

Work Area Compliance Method

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The work area approach facilitates work with code officials who are less sophisticated concerning historic preservation or who are less able to spend significant time on the project. Consider this approach when the design team can take a strong lead in the process.



One advantage of the work area approach is that its tiered system defines level of work and establishes proportionate expectations for code compliance

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at each level. This increases predictability of cost and time earlier in the project than is the case with the other IEBC approaches. 

Especially for large or involved projects, avoid the work area approach if the design office lacks experience in code questions or historic preservation, unless a properly experienced consultant can be added to the team for this purpose.



The work area approach spells out reasonable requirements for occupancy change to a greater extent than either the prescriptive or performance approach and thus may be the best choice in that situation.

Performance Compliance Method 

The performance approach quantifies the analysis of fire safety, means of egress, and general safety. It is thus best suited to projects where these are the principal issues and where quantification of otherwise subjective judgments is needed.



In-house use of the performance approach can be a helpful tool for design teams to pin down areas where improvements are needed and to organize their proposals for alternatives under either the prescriptive or the work area approach.

RESTORATION Background and Definitions According to the Introduction to the Standards, Restoration, the third treatment, focuses on the retention of materials from the most significant time in a property’s history, while permitting the removal of materials from other periods.

Restoration is probably the least well-understood approach to historic structures, especially among laymen. Restoration is not a casual evocation of an imagined past. When a building is restored, it must be restored to a documented condition. A key concept in restoration is the “restoration period,” that is, the point in time to which the appearance of the building is to be returned. This could be its date of construction, or it might be a time at which an important event associated with the building occurred. In either case, photographs or drawings must exist to provide a model for the work. The Secretary of the Interior’s Standards specifically prohibit “conjectural restoration” or substitution of typical elements from the restoration period for those that were actually in place. Given adequate documentation, restoration may involve fairly extensive work, but it is easier if most of the architectural fabric of the restoration period is in place. The assumption in restoration is that the project produces a building that is very nearly identical in every respect to the original building. In effect, restoration is a “time machine.”

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Secretary of the Interior’s Standards for Restoration 1. A property will be used as it was historically or be given a new use which reflects the property’s restoration period. 2. Materials and features from the restoration period will be retained and preserved. The removal of materials or alteration of features, spaces, and spatial relationships that characterize the period will not be undertaken. 3. Each property will be recognized as a physical record of its time, place, and use. Work needed to stabilize, consolidate and conserve materials and features from the restoration period will be physically and visually compatible, identifiable upon close inspection, and properly documented for future research. 4. Materials, features, spaces, and finishes that characterize other historical periods will be documented prior to their alteration or removal. 5. Distinctive materials, features, finishes, and construction techniques or examples of craftsmanship that characterize the restoration period will be preserved. 6. Deteriorated features from the restoration period will be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature will match the old in design, color, texture, and, where possible, materials. 7. Replacement of missing features from the restoration period will be substantiated by documentary and physical evidence. A false sense of history will not be created by adding conjectural features, features from other properties, or by combining features that never existed together historically. 8. Chemical or physical treatments, if appropriate, will be undertaken using the gentlest means possible. Treatments that cause damage to historic materials will not be used. 9. Archeological resources affected by a project will be protected and preserved in place. If such resources must be disturbed, mitigation measures will be undertaken. 10. Designs that were never executed historically will not be constructed.

Application to Specific Projects This approach is most often chosen for buildings with a fairly short period of importance to history or that represent, as originally built, the work of an important architect. However, restoration is a possible approach whenever thorough documentation is available, the principal question of its desirability revolving around the quality and interest of any work that would be removed in the restoration process. Examples of buildings that might be chosen for this treatment could include 

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A building where a treaty or other important historical document was prepared or signed. The restoration would be the time of the event from which the building derives its importance.

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Restoration



The home of a person of great significance in politics, the arts, the sciences, and so forth. The restoration period would be the time when the building was occupied by the significant owner.



A building with no specific important associations but from a significant period in the development of a region, such as a house from the earliest period of a state’s development. Such a building would have to have been thoroughly documented prior to any inappropriate alterations.



An otherwise minor historic structure that has been severely and inappropriately altered, and for which adequate documentation of a former condition exists.

231

Restoration and Building Code Provisions Restoration involves a detailed understanding of the original design and detailing of the building, whether the historic fabric is intact or not. The discussion in the previous section on rehabilitation is appropriate to restoration with the following additional suggestions. Prescriptive Compliance Method If the building is substantially unaltered since construction, basic life safety needs will require review. Such an analysis may reveal deficiencies that will affect the project significantly. For example, if a Victorian house in an old downtown area is converted to an office, windows in the side walls may be too close to the property line, based on IBC requirements. In addition, the wooden walls would not have the required fire rating. Changing these features to conform to the code would almost certainly result in violations of the Secretary of the Interior’s Standards. Work Area Compliance Method The historic provisions of the work area compliance method would probably offer the greatest flexibility in upgrading a historic structure but also would require an understanding of the code intent and careful development of the required report on how the intent of the code is to be met. In the case of the Victorian house discussed previously, the change of occupancy to office use would not require any changes in the side walls or windows, because the relative hazard as classified by Table 912.6 has not increased. Performance Compliance Method The performance compliance method, in many cases, will require significant interventions. This is particularly true where fire safety and exiting considerations arise. This approach requires a complete evaluation of the life safety systems of a building, which may be complex, even for a small project. In the example case, the performance compliance method would not require review of potential fire spread between buildings.

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RECONSTRUCTION Background and Definitions Reconstruction is re-creation of a historic structure that no longer exists. For example, a building could be reconstructed soon after it is destroyed in a disaster, or it may reemerge decades after its disappearance as a result of public regret at its loss. Like restoration, reconstruction demands a certain, documented knowledge of the building’s appearance, construction, and details. Unlike restoration, reconstruction typically begins with little or nothing. It is the most difficult of the four approaches described under the Secretary of the Interior’s Standards. Concerning reconstruction, the Introduction to the Standards says: Reconstruction, the fourth treatment, establishes limited opportunities to re-create a nonsurviving site, landscape, building, structure, or object in all new materials.

Such projects occupy an ambiguous position in historic preservation. To be historically honest, a reconstructed structure must be a perfect “clone” of the original, but this is extremely difficult to achieve. An accurate reconstruction must be based on documentation of a rare quality and detail; as a result, many “reconstructions” over the years have been inauthentic and of dubious value. To avoid such problems, the building must not be interpreted as a historic building, but only as a reminder of a lost structure. Far from concealing this disadvantage, the building’s story must highlight it. The public must never be led to believe that they are seeing the real thing. Nevertheless, the building must, to the greatest degree possible, be indistinguishable from the original.

Secretary of the Interior’s Standards for Reconstruction 1. Reconstruction will be used to depict vanished or non-surviving portions of a property when documentary and physical evidence is available to permit accurate reconstruction with minimal conjecture, and such reconstruction is essential to the public understanding of the property. 2. Reconstruction of a landscape, building, structure, or object in its historic location will be preceded by a thorough archeological investigation to identify and evaluate those features and artifacts which are essential to an accurate reconstruction. If such resources must be disturbed, mitigation measures will be undertaken. 3. Reconstruction will include measures to preserve any remaining historic materials, features, and spatial relationships. 4. Reconstruction will be based on the accurate duplication of historic features and elements substantiated by documentary or physical evidence rather than on conjectural designs or the availability of different features from other historic

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properties. A reconstructed property will re-create the appearance of the nonsurviving historic property in materials, design, color, and texture. 5. A reconstruction will be clearly identified as a contemporary re-creation. 6. Designs that were never executed historically will not be constructed.

Application to Specific Projects Reconstruction is rarely chosen as an approach, unless the building being duplicated is one of great importance to the history and imagination of the community. Especially if the building is a large one with significant life safety and accessibility issues, the result can be conflicting objectives. The owner and the community may mobilize strong pressure for approval of the project but may not understand the requirement for historical authenticity. Their reaction to code problems may be to jettison the project’s accuracy and settle for an impressionistic approximation of the original, one that lacks sufficient historic quality to justly qualify for any code leeway at all. Regulatory officials are likely to understand the political implications of flagship projects of this type, but, like building owners, may not appreciate the need for accuracy. An added consideration is that, if the reconstruction is a high-visibility project, any future problem with the building would receive significant attention and publicity. The code official will view the reconstruction as an opportunity to correct perceived deficiencies and may be less inclined to approve alternatives, because they are dictated by good preservation practice rather than by existing conditions. As a result, design professionals must be prepared to address convictions from both the building owner and the code official to the effect that the authenticity required by the Secretary of the Interior’s Standards is less important than questions of budget and schedule, and fears—real or imaginary—concerning personal liability.

Reconstruction and Building Code Provisions In terms of almost all codes, a reconstruction is a new building. Especially in localities that do not specifically designate a reconstruction as eligible for consideration as a historic structure, the architect or engineer must produce a solution that meets the requirements of both the code for new construction and the Secretary of the Interior’s Standards. In addition, such a solution must be efficient in terms of both time and cost. Reconstruction is impossible without a fairly complete set of architectural drawings of the original building. With these in hand, the designer must begin by performing a plan check of the historical drawings under the current code for new construction. Correction of structural deficiencies without affecting the appearance of the building may be fairly straightforward, and the Secretary of the Interior’s Standards would not oppose modifications of this type.

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More difficulty is likely to be encountered with deficiencies in exiting and accessibility. Problems may arise with arrangement, size, and numbers of exits, and with overall accessibility, including both horizontal clearances and vertical barriers such as steps and thresholds. At this point, the designer faces conflicting requirements. The Secretary of the Interior’s Standards call for fairly stringent adherence to a set of plans that almost certainly contain significant nonconformities from the current regulatory point of view. However, the International Building Code does contain provisions that help to resolve this dilemma.

International Building Code, Sections 104.10–104.11.2 104.10 Modifications. Wherever there are practical difficulties involved in carrying out the provisions of this code, the building official shall have the authority to grant modifications for individual cases, upon application of the owner or owner’s representative, provided the building official shall first find that special individual reason makes the strict letter of this code impractical and the modification is in compliance with the intent and purpose of this code and that such modification does not lessen health, accessibility, life and fire safety, or structural requirements. The details of action granting modifications shall be recorded and entered in the files of the department of building safety. 104.11 Alternative materials, design and methods of construction and equipment. The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety. 104.11.1 Research reports. Supporting data, where necessary to assist in the approval of materials or assemblies not specifically provided for in this code, shall consist of valid research reports from approved sources. 104.11.2 Tests. Whenever there is insufficient evidence of compliance with the provisions of this code, or evidence that a material or method does not conform to the requirements of this code, or in order to substantiate claims for alternative materials or methods, the building official shall have the authority to require tests as evidence of compliance to be made at no expense to the jurisdiction. Test methods shall be as specified in this code or by other recognized test standards. In the absence of recognized and accepted test methods, the building official shall approve the testing procedures. Tests shall be performed by an approved agency. Reports of such tests shall be retained by the building official for the period required for retention of public records.

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These provisions are intended to foster responsible innovation, but they can equally be used to develop an acceptable set of alternatives for an archaic structure. To apply these provisions to a reconstruction project, the designer should consider the following:

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The best code approach for a reconstruction project is probably the prescriptive approach.



Meetings with regulatory officials must be undertaken early, and the designer must approach the project as a well-informed and cooperative member of a team that includes the regulatory officials.



Be aware of each of the building’s deficiencies. One way to analyze problems is to use the performance approach as an in-house evaluation tool. This will promote an understanding of the issues that will be considered significant from a code point of view and may suggest alternatives that will satisfy overall safety objectives.

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CHAPTER

18

Resources

HISTORIC BUILDINGS The National Trust for Historic Preservation has encouraged the rehabilitation and reuse of historic buildings for many years. Their web site lists a number of publications for use in rehabilitation projects. www.preservationnation.org The National Park Service, Technical Preservation Services, has numerous pamphlets and books on the technical aspects of existing building repair and restoration. www.nps.gov The General Services Administration is another source for publications and guidance for rehabilitation. www.gsa.gov The Association for Preservation Technology, International is another source for technical information on existing structures. www.apti.org

NATURAL HAZARDS INFORMATION FEMA, the Federal Emergency Management Agency, has a large program for risk reduction and mitigation for natural hazards. The publications are available at no cost and can be downloaded for use. This includes earthquake, flood, coastal storm surge, wind, and fire conditions. www.fema.gov The FEMA publications that have gone through the consensus process and are now national standards may be obtained from the American Society of Civil Engineers. ASCE 31 and ASCE 41 are adopted by reference in the IEBC. www.asce.org The U.S. Geological Survey provides information on the seismic risks at any site in the United States, as well as information on other natural hazards. www.usgs.gov The National Institute of Standards and Technology (NIST) has conducted extensive research on many aspects of building performance, including natural hazards and fire. www.nist.gov 237

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Resources

The National Oceanic and Atmospheric Administration provides weather and hurricane information. www.noaa.gov

FIRE SAFETY The National Fire Protection Association (NFPA) is the primary source for standards on fire protection. www.nfpa.org

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INDEX Abatement codes, 19, 20 Accessibility: for additions, 126 and change of occupancy, 129, 143 exceptions for technical infeasibility, 88, 143 in historic buildings, 145, 147 in historic reconstructions, 234 in performance compliance method, 156 in prescriptive compliance method, 101, 155–156 in work area compliance method, 113, 116, 143 Accessory uses, 160 Accuracy, in historic preservation, 215–216 Adaptive reuse, 126, 142, 146. See also Change of occupancy Additions: code compliance for, 77 defined, 125 in flood-hazard areas, 25, 99 to historic buildings, 26 performance compliance method for, 155, 156 prescriptive compliance method for, 98–101 work area compliance method for, 125–126 Age of users, as occupancy factor, 41 Alterations: defined, 115, 117 finishes and systems, 97 in flood-hazard areas, 99 to historic buildings, 115, 145 Level 1, 115–116, 120, 121 Level 2, 116–118, 122–123 Level 3, 118–119 nonstructural, 97 performance compliance method for, 155, 156 prescriptive compliance method for, 98–101 repairs, distinction from, 115 in restoration of historic buildings, 218 that add structural loads, 77 structural verification for, 116

structural work triggered by, 115–116 work area compliance method for, 111, 115–123, 139, 145 Alternatives to code provisions, 79 alternate materials and methods, 85 for historic building change of occupancy, 126 when technically infeasible, 88 American Antiquities Act of 1906, 211 American Public Health Association (APHA), 72 American Society of Civil Engineers, 237 Apartments, 62 additions to, 125 change in occupancy to, 131–132 exit enclosures for, 75 Area, see Height and area Assembly occupancies (Group A), 43–45 Association for Preservation Technology, International, 237 Banks, 46 Banquet halls, 43 Bars, 43 Barns, 61 Basic Building Code, 17 BOCA Basic/National Existing Structures Code, 24 BOCA/National Building Code (1987), 17, 32 BOCA Uniform Building Code (1987), 23 Brick Act of 1814, 15 Building and component size, 10, 71–72 Building codes, 5–7, 9–10, 82 Building Exits Code (1927), 16 Building Officials and Code Administrators International (BOCA), 17 Building permits: and building department liability, 81 and code compliance, 76 historic building’s history of, 76 and updating of codes, 82 Business occupancies (Group B), 46–47 California historic building code, 33–34 Cannery Row (John Steinbeck), 145, 146 Certificate of Occupancy (C of O), 86

239

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INDEX

Change of occupancy, 28–29, 77–80 applying work area compliance method to, 137–139 approvals for existing buildings, 28–29 approvals for nonconforming existing buildings, 19, 22 change in character of use, 131 change in classification or group, 131–137, 139–143 and exterior wall construction, 136–137 heights and areas, 136 for historic buildings, 146–147 under IEBC, 80 and means of egress, 132–136 performance compliance method for, 155, 156 prescriptive compliance method for, 101–103, 106–107 structural requirements with, 102 Uniform Code for Building Conservation, 24 work area compliance method for, 126–143, 146–147 Chicago Building Code (1875), 15 Code cycles, 82 Church preservation, 218–221 Cities, 63–64 Clinics, 46 College buildings, 46 Compartmentation between units, 158 Compliance, 6–7 for additions, 125 for change of occupancy, 28 for high-rise structures, 93–95 for nonconforming existing buildings, 19 when moving up in risk, 22 Compliance methods (IEBC), 81–83, 205–208. See also each specific method example applications of, 90–95 for high-rise buildings, 208 for low-rise buildings, 205–207 performance, 30, 89–90 prescriptive, 29, 88 selection of, 82–84 work area, 29–30, 89 Concrete structures: relocation of, 147–150 structural repair of, 114–115 Condition of users, as occupancy factor, 41 Construction documents: for historic reconstructions, 233 under IEBC, 85–88

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Construction methods, alternative, 85 Construction type, 65–71 fire safety concerns, 69–71 general groups for, 65–66 health and habitability, 71 for historic buildings, 76 noting of, 43 and prescriptive compliance method, 104 Type I, 67 Type II, 67 Type III, 67–68 Type IV, 68 Type V, 69 Continuity of history, in historic preservation, 218 Convalescent facilities, 51 Corridors: dead-end, 72, 159 in historic buildings, 70, 109, 146 performance compliance method for, 158, 159 prescriptive compliance method for, 102, 108, 109 work area compliance method for, 113, 117, 122, 123, 134, 141, 146 Damage, substantial vs. less than substantial, 98 Dance halls, 44 “Dangerous buildings, 86–87, 114 Day care facilities, 47, 54–55 Density of users, as occupancy factor, 41 Dead-end corridors, 72, 159 Department stores, 55 Disease, spread of, 64 Dormitories, 56 Earthquake-damaged buildings, 98, 114. See also Seismic requirements Earthwork, in historic areas, 218 Educational buildings, 46, 47 Educational occupancies (Group E), 47 Egress, see Exiting (egress) Electrical system: and change in occupancy, 139 in prescriptive compliance method, 101 in work area compliance method, 113, 139 Elevator controls, 159 Energy conservation, 101, 113 Epidemiology, 15 Europe, city fires in, 63

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INDEX

Executive Order 11593 (1971), 212 Existing buildings, 19–30. See also specific topics change of occupancy, 28–29, 79–80 International Building Code, 24–28 International Building Code (2009), 75 International Existing Building Code, 29–30 materials in, 65 nonconforming rights, 79 principles of regulating, 75–80 regional model codes, 19–24 structural elements in, 65 Exiting (egress): and change of occupancy, 101, 140–143 in construction documents, 85–86 and fire safety, 16, 72 in historic buildings, 102 as occupancy factor, 42 performance compliance method for, 159 speed of, 98 work area compliance method for, 113, 117–119, 140–143 Exterior wall construction, 136–137, 142 Factories, 16 Factory and Industrial occupancies (Group F), 47–49 Federal Emergency Management Agency (FEMA), 237 Federal Housing Administration, 36 Federal legislation (historic buildings), 34–35 Fires: flow of, 117–118 major U.S. city and building fires, 13–14 in mercantile occupancies, 55 repairing damage from, 98 in residential occupancies, 57 risk of life and property loss in, 98 Fire alarm and detection systems, 140, 158–159 Fire escapes, 101 Fire-extinguishing systems, 159 Fire protection/resistance: and change in occupancy, 140 and construction types, 65–71 and exterior wall construction, 136–137 for historic buildings, 85, 145–147 in work area compliance method, 113, 117–119, 140

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241

Fire safety. See also Performance compliance method and building and component size, 72 and change of occupancy, 101, 142–143 and construction and materials types, 69–71 and distance between buildings, 64 and hazard ratings, 142 in historic buildings, 102 as occupancy factor, 41–42, 61–62 resource for, 238 and siting, 63–64 standards for life safety vs., 129 and structural elements, 64 Flood hazard areas: additions in, 125 International Building Code compliance, 156 in prescriptive compliance method, 99 Fuel gas alterations, 101 Garages, 61 Gaslamp Quarter Code “Cookbook,” 34 General Services Administration, 237 Glass, 101 Glazing, 71, 113 Government buildings, 46 Great Baltimore Fire (1904), 16 Great Chicago Fire, 64 Greenhouses, 61 Guardrail heights, 72 Guidelines for Rehabilitation, Restoration, and Reconstruction, 213, 215, 223 Habitable rooms, 72 Handrails, 141 Hazards: and change of occupancy, 77–78, 80 and definitions of “dangerous,” 86–87 exposure of exterior walls, 136–137 factors producing, 79 in historic buildings, 78, 80 information resources for, 237 means of egress categories, 132–135 and nonconforming rights, 79 Hazardous contents, as occupancy factor, 41 Hazard tables, 24, 104, 142 Health and safety, 5, 15. See also Fire safety; Life safety and building and component size, 72 and construction and materials types, 71

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INDEX

Health and safety (cont’d ) minimum levels for new and existing buildings, 20 as occupancy factor, 41–42 risks to, 10 siting for, 64 Height and area, 10, 98 for additions, 77, 125 and change of occupancy, 136 and fire safety, 72 hazard-ranking table for, 142 for historic buildings, 98 and nonconforming rights, 79 in performance compliance method, 158 and prescriptive compliance method, 104 in work area compliance method, 136 High-hazard occupancies (Group H), 50–51, 156 High-rise structures: compliance for, 93–95, 208 construction type for, 67 occupancy classification of, 62 performance compliance evaluation with required improvements, 199–204 performance compliance safety evaluation, 184–199 prescriptive compliance method for, 105, 107–109 safety concerns for, 20 work area compliance method for, 121–123 Historic American Building Survey (HABS), 211 Historic buildings, 31–37 addition to, 155 alterations to, 115, 145, 155 change in character of use for, 131 change of occupancy, 80, 102, 146–147, 155 competing objectives for, 3–4 construction types, 67–69 dangerous, 86–87 energy requirements, 113 federal agency regulation, 35–36 federal legislation, 34–35 flood requirements exemption, 99, 144 heights and areas, 98 impossibility of compliance for, 22 International Building Code, 32–33, 97–98 International Building Code (2009), 78

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International Existing Building Code, 33, 87 materials in, 65, 85 performance compliance method, 155 prescriptive compliance method for, 97–99, 102, 103 regional model codes, 31–32 relocated, 147–150, 155 repairs to, 113, 145, 155 resources for, 237 seismic report for, 144, 147 specific information needed for, 76 state building codes, 33–34 structural elements in, 65 structural repairs in, 114 tax incentives for, 35 upgrading for change of occupancy, 141 work area compliance method for, 113, 114, 143–150 Historic designations, 76 Historic fabric, 134, 141 Historic preservation. See also Preservation approach accuracy vs. subjectivity in, 215–216 adaptive reuse requirements, 126 of an historic church, 218–221 continuity of history in, 218 federal regulation of, 5 legal basis for, 211–214 preservation approach to, 224–226 reconstruction approach to, 232–235 rehabilitation approach to, 226–229 reproduction vs. original features in, 217 restoration approach to, 229–231 reversibility in, 217–218 treatment approaches for, 223–224 underlying philosophy of, 215 of a Victorian house, 221–222 Historic Preservation Overlay Zones (HPOZ), 214 Historic Sites Act of 1935, 211–212 Hollyhock House (Los Angeles, California), 144 Hospitals, 51 Hotels, 56, 62, 75, 125 Housing Code (APHA), 72 Housing codes, 19 HVAC, see Mechanical systems Ignition sources, as occupancy factor, 42 Incidental uses, 159, 160 Industrial activities (in Group F), 47–49

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INDEX

Institutional occupancies (Group I), 51–55, 156 Interior finishes, as occupancy factor, 42 International Building Code (in general), 16, 17, 24–25, 29 alternate materials and methods in, 85 change of occupancy, 77–78 construction type classifications, 65–69 exceptions for historic buildings, 144–145 for existing buildings, 24–28, 76 existing structures, 75 fire alarm and detection systems in, 140 fire protection systems in, 140 for flood hazard areas, 156 for historic buildings, 32–33, 78 on historic reconstructions, 234 light and ventilation in, 140 for means of egress, 134, 135 occupancy classifications in, 42–61, 126, 127 performance compliance tables based on, 155 and prescriptive compliance method, 97 structural safety compliance with, 89–90 in the United States, 17 International Conference of Building Officials (ICBO), see Uniform Building Code International Building Code (2009): Assembly Group A, 44–45 Business Group B, 46–47 change of occupancy, 77–78 construction type classifications, 66–69 Educational Group E, 47 for existing buildings, 25–28, 76 existing structures section, 75 Factory and Industrial Group F, 48–49 High-hazard Group H, 50–51 for historic buildings, 32–33, 78 Institutional Group I, 52–54 Mercantile Group M, 56 occupancy classifications in, 42–43, 126, 127 Residential Group R, 57–58 Storage Group S, 58–60 Utility and Miscellaneous Group U, 61 International Building Code (2012): Institutional Group I, 54–55 occupancy classifications in, 43 International Code Council (ICC), 5, 17, 81

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243

International Existing Building Code (IEBC), 4–5, 29, 75, 214 alternate materials and methods in , 85 Appendix A of, 114 compliance methods under, 81–82 edition cycles, 82 examples of compliance methods, 90–95 existing buildings, 29–30 historic buildings, 33, 87 italicized text within, 82 and occupancy change, 80 organization of, 81–88 performance compliance method, 89–90, 155–204 plan requirements, 85–88 prescriptive compliance method, 88, 97–109 reasons for using, 81 on seismic loads, 84 on selection of compliance methods, 82–84 on “technically infeasible,” 88 updating of, 82 work area compliance method, 89, 111–123 International Fire Code, 156 International Mechanical Code, 140 International Plumbing Code, 140 International Property Maintenance Code, 156 Iroquois Theater Fire (1903), 16 Japan, fires in, 55 Lecture halls, 44 Legal information (historic buildings), 76 Libraries, 44 Life safety. See also Performance compliance method and change of occupancy, 101 and fire safety standards, 129 major city and building fires, 13–14 and risk, 98 in work area compliance method, 116–117 Life Safety Code (NFPA 101), 16 Light, 64, 140 Lighting, 159 Livability, 216 Local codes/laws, 15, 16, 214 Low-hazard industrial occupancies, 47–49 Low-hazard storage occupancies, 58–60

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244

INDEX

Low-rise buildings: compliance for, 90–93 compliance methods for, 205–207 performance compliance for change of occupancy (M to A2), 178–184 performance compliance for change of occupancy (M to B), 173–178 performance compliance safety evaluation, 160–173 prescriptive compliance method for, 105–107 work area compliance method for, 120–121, 150–153 Massachusetts historic building code, 34 Materials of construction, 10, 65–71 alternate, 85 construction types, 66–69 fire safety concerns, 69–71 health and habitability, 71 for historic buildings, 216, 217, 224–226 for nonstructural alterations, 97 for nonstructural elements, 77 prescriptive compliance method for, 107–109 for repairs, 113 retention of, 224 Mechanical systems: and change in occupancy, 140 in performance compliance method, 158 in prescriptive compliance method, 101 in work area compliance method, 113, 119, 140 Mercantile occupancies (Group M), 55–56 Mission San Gabriel, 1 Model codes, 5, 15–17, 36, 214. See also International Building Code; Regional model codes Moderate-hazard industrial occupancies, 47–49 Moderate-hazard storage occupancies, 58–59 Moved historic buildings, 147–150 Mumford, Lewis, 212 Museums, 44 National Board of Fire Underwriters, 16 National Building Code, 16, 17 National Bureau of Standards (NBS), 34–36, 213 National Conference of States on Building Codes and Standards (NCSBCS), 36

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National Environmental Policy Act of 1969, 35, 212 National Fire Protection Association (NFPA), 16, 238 National Historic Preservation Act of 1966, 34–35, 212 National Institute of Building Sciences, 36 National Institute of Standards and Technology (NIST), 34, 237 Nationally Applicable Recommended Rehabilitation Provisions (NARRP), 36 National Oceanic and Atmospheric Administration, 238 National Park Service, 211 National Park Service, Technical Preservation Services, 237 National Register of Historic Places, 35, 211 National Trust for Historic Preservation, 4, 237 Natural hazards information, 237 New Jersey historic building code, 34 New Jersey Rehabilitation Subcode, 34 New work. See also Additions on historic buildings, 26 historic reconstruction as, 233 nonhistoric buildings, 97 prescriptive compliance method for, 106–108 New York City, 15 Night clubs, 43 Nonconforming buildings, 19–20, 101 Nonconforming rights, 76 and change of occupancy, 80 for existing buildings, 79 Nonstructural alterations and repairs: materials of construction for, 97 in prescriptive compliance method, 100 in work area compliance method, 113, 116–117 Nonstructural elements, 77 Occupancy, 41–62. See also Change of occupancy Certificate of Occupancy, 86 classification of, 42–43. See also Occupancy groups classifications in previous codes, 61–62 and construction type, 69–70 defined, 10 factors influenced/determined by, 41–42 historic building records of, 76

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INDEX

and nonconforming rights, 79 and siting regulation, 63 Occupancy groups: Assembly (Group A), 43–45 Business (Group B), 46–47 change in character of use within, 128, 131 Educational (Group E), 47 Factory and Industrial (Group F), 47–49 High-hazard (Group H), 50–51 Institutional (Group I), 51–55 Mercantile (Group M), 55–56 noting of, 43 Residential (Group R), 56–58 Storage (Group S), 58–60 Utility and Miscellaneous (Group U), 61 Offices, 46, 62 One-family dwellings, 56, 62 One-story commercial buildings, see Lowrise buildings Operational controls, 85, 119, 144 Pacific Coast Building Code, 16 Pacific Coast Building Officials, 16 Paraguay, fires in, 55 Pennsylvania Station (New York), 212 Performance compliance method, 30, 89–90, 155–204 additional code requirements with, 156 for high-rise building safety evaluation, 184–199 for high-rise building with required improvements, 199–204 for historic building rehabilitation, 229 for historic building restoration, 231 information needed for, 157 for low-rise building change of occupancy (M to A2), 178–184 for low-rise building change of occupancy (M to B), 173–178 for low-rise building safety evaluation, 160–173 procedure in, 156–160 safety parameter numerical values in, 157–158 safety parameters evaluated in, 158–160 Planning and construction factors, 63–72 building and component size, 71–72 siting, 63–64 type of construction and materials, 65–71 Plan requirements, 85–88 Plate glass, 71

bindex.indd 245

245

Plumbing system: and change in occupancy, 140 in prescriptive compliance method, 101 in work area compliance method, 113, 140 Portsmouth, New Hampshire, 15 Predictability, in work area method, 111 Prescriptive compliance method, 29, 88, 97–109 additions, alterations, and repairs, 98–101 change of occupancy, 101–103 evaluating effectiveness of, 103–105 for high-rise office building, 105, 107–109 for historic building reconstruction, 235 for historic building rehabilitation, 228 for historic building restoration, 231 for low-rise mercantile buildings, 105–107 performance compliance approach with, 204 Preservation approach, 224–226. See also Historic preservation buildings suited for, 223 defined, 224 Secretary of the Interior’s Standards for, 224–225 as treatment approach, 223 Prisons, 51 Private garages, 61 Property loss, 13–14, 98 Property maintenance codes, 19 Property owner rights, societal needs vs., 14–15, 56, 75 Proportionality, in work area method, 111 Public safety, responsibility for, 9 Reconstruction (historic buildings), 232–235 buildings suited for, 224 Secretary of the Interior’s Standards for, 232–233 as treatment approach, 223 Reform, regulations resulting from, 15 Regional model codes: for existing buildings, 19–24 for historic buildings, 31–32 in the United States, 16–17 Rehabilitation: building department liabilities in, 81 buildings suited for, 223 of historic buildings, 80, 216, 226–229 under IEBC, 29–30

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246

INDEX

Rehabilitation (cont’d ) limitations of approaches to, 24 methods for dealing with, 20 regulation of, 76–79 restoration vs., 216 Secretary of the Interior’s Standards for, 226–227 as treatment approach, 223 “25-50 percent rule” for, 20–22 Rehabilitation Guidelines (HUD), 36, 85 Reinforced concrete/masonry buildings, 114 Religious buildings, 44 Religious education facilities, 47 Relocated historic buildings, 147–150 Remodeling approvals, 19 Repairs: alterations vs., 115 defined, 112–113 to historic buildings, 143, 145, 225 in historic preservation, 217 nonstructural, 100, 113 performance compliance method for, 155 prescriptive compliance method for, 98–101 structural, 113–115 substantial vs. less than substantial, 114 work area compliance method for, 112–115, 145 Reproduction, in historic preservation, 217 Residential care facilities, 56 Residential occupancies (Group R), 56–58 Restaurants, 43 Restoration, 216, 229–231 buildings suited for, 224 conjectural, 229 local sentiment favoring, 225 Secretary of the Interior’s Standards for, 229, 230 as treatment approach, 223 Restoration period, 229 Retroactive requirements, 6–7, 19, 75 Reversibility, in historic preservation, 217–218 Risk, 9–10, 44, 46, 58, 62, 72 Roofs and roofing, 115–116, 118 Safety. See also Fire safety; Health and safety; Life safety evaluating parameters of, see Performance compliance method factors producing, 79

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in high-rise structures, 20 in historic building rehabilitation, 216 operational controls for, 85 retroactive requirements for, 75 Schools, fire safety standards for, 16 The Secretary of the Interior’s Standards for Historic Preservation Projects (1978), 212 The Secretary of the Interior’s Standards for Treatment of Historic Properties, 36, 212–214 Guidelines for, 213 and new materials/equipment, 216 objective of, 223 philosophy underlying, 215 for preservation, 224–225 for reconstruction, 232–233 for rehabilitation, 226–227 reproduction, 217 for restoration, 229, 230 treatment approaches in, 223 Seismic requirements, 26, 84, 98 and change of occupancy, 28, 29 for historic structures, 144 International Building Code, 24–26 in prescriptive compliance method, 99–100, 104 for unreinforced masonry buildings, 75 in work area compliance method, 116, 138–139, 144 voluntary improvements, 26 Separation between units, 158 Separation of occupancies, 159–160 Shafts, see Vertical openings Siting, 10, 63–64 fire concerns, 63–64 health and habitability, 64 and prescriptive compliance method, 103–104 for relocated historic buildings, 147 Smoke control, 159 Societal needs, property owner rights vs., 14–15, 56, 75 Southern Building Code (1945), 17 Southern Building Code Congress, 17 Southern Standard Building Code, 17 Stairs: addition of, 20 alteration or replacement of, 77 and change of occupancy, 134 exiting, 141

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INDEX

and fire safety, 72 in historic buildings, 141 and nonconforming rights, 79 in prescriptive compliance method, 100 in work area compliance method, 134 Standard Building Code, 17 Standard Existing Building Code, 24 Standard of care, 81 Standpipes, 159 State building codes, 33–34, 213 State environmental laws, 213–214 State Historical Preservation Office (SHPO), 35 State Historic Building Code (California), 33 State Historic Building Safety Code (California), 33–34 State laws and regulations, 87, 213–214 State registers of historic places, 213 Steinbeck, John, 145, 146 Storage occupancies (Group S), 58–60 Structural changes: under IEBC, 97, 98 in prescriptive compliance method, 99–100 in work area compliance method, 113–118 Structural collapse, risk of, 10 Structural elements: in alterations, 77 in existing and historic buildings, 65 and fire safety, 64 load-bearing, 70–71 and occupancy, 42 repairing damage to, 98, 100 Structural loads: for additions, 125 alterations that add, 77 under IEBC, 98 and nonconforming rights, 79 in prescriptive compliance method, 99 in work area compliance methods, 137 Structural requirements, for change of occupancy, 102, 147 Structural safety, 89–90 Subjectivity, in historic preservation, 215–216 Tax incentives, 35, 214 Technically infeasible, 88 Tenement House Act (1867), 15 Theaters, 43, 62

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247

Training facilities, 46 Triangle Shirtwaist Fire (1911), 16 25-50 percent rule, 20–22, 35–36 Two-family dwellings, 56, 62 Two-story commercial buildings, see Lowrise buildings Uniform Building Code (1976), 21, 31–32 Uniform Building Code (1979), 22–23 Uniform Building Code (1982) (UBC), 6, 16, 17 Uniform Code for Building Conservation (UCBC), 24, 104 U.S. Consumer Product Safety Commission (CPSC), 71 U.S. Department of Commerce, 35–36 U.S. Department of Housing and Urban Development (HUD), 36 U.S. Department of the Interior, 36 U.S. Geological Survey, 237 Unreinforced masonry buildings, 75, 114 Updating codes, 6, 17, 82 Upgrading requirements: for change of occupancy, 139–143 for structural repair, 113 Unsafe buildings, 156 Utility and Miscellaneous occupancies (Group U), 61 Venice Charter of 1964, 36 Ventilation: and change in occupancy, 140 for health and habitability, 64 in work area compliance method, 140 Vertical openings, 71, 142–143 enclosure of, 123, 141, 142 means of egress through, 119 performance compliance method for, 158 spread of fire and smoke through, 117, 142 Voluntary improvements, 26 Wheelchair-accessible egress, 72 Wing Chong market (Monterey, California), 145, 146 Wood frame buildings, 114 Work area: and classification of alterations, 118 defined, 89, 111 Work area compliance method, 29–30, 89, 111–123, 125–153

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Work area compliance method (cont’d ) additions, 125–126 for alterations, 115–123 change of occupancy, 126–143 for historic buildings, 143–150, 228–229, 231

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for low-rise buildings, 150–153 for repairs, 112–115 Wright, Frank Lloyd, 144 Zoning, for historic buildings, 76

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